docs: Use :doc: role when linking to commands

This makes it so we link to the very top of the document instead of a
special anchor we manually include.

So clicking e.g. :doc:`string <cmds/string>` will link you to
cmds/string.html instead of cmds/string.html#cmd-string.

I would love to have a way to say "this document from the root of the
document path", but that doesn't appear to work, I tried
`/cmds/string`.

So we'll just have to use cmds/string in normal documents and plain
`string` from other commands.

doc_src/fish_for_bash_users.rst

@@ -14,7 +14,7 @@ Command substitutions
 
 Fish spells command substitutions as ``$(command)`` or ``(command)``, but not ```command```.
 
-In addition, it only splits them on newlines instead of $IFS. If you want to split on something else, use :ref:`string split <cmd-string-split>`, :ref:`string split0 <cmd-string-split>` or :ref:`string collect <cmd-string-collect>`. If those are used as the last command in a command substitution the splits they create are carried over. So::
+In addition, it only splits them on newlines instead of $IFS. If you want to split on something else, use :doc:`string split <cmds/string-split>`, :doc:`string split0 <cmds/string-split>` or :doc:`string collect <cmds/string-collect>`. If those are used as the last command in a command substitution the splits they create are carried over. So::
 
   for i in (find . -print0 | string split0)
 
@@ -23,7 +23,7 @@ will correctly handle all possible filenames.
 Variables
 ---------
 
-Fish sets and erases variables with :ref:`set <cmd-set>` instead of ``VAR=VAL`` and a variety of separate builtins like ``declare`` and ``unset`` and ``export``. ``set`` takes options to determine the scope and exportedness of a variable::
+Fish sets and erases variables with :doc:`set <cmds/set>` instead of ``VAR=VAL`` and a variety of separate builtins like ``declare`` and ``unset`` and ``export``. ``set`` takes options to determine the scope and exportedness of a variable::
 
   # Define $PAGER global and exported,
   # so this is like ``export PAGER=less``
@@ -132,7 +132,7 @@ See :ref:`Quotes <quotes>` for more.
 String manipulation
 -------------------
 
-Fish does not have ``${foo%bar}``, ``${foo#bar}`` and ``${foo/bar/baz}``. Instead string manipulation is done by the :ref:`string <cmd-string>` builtin.
+Fish does not have ``${foo%bar}``, ``${foo#bar}`` and ``${foo/bar/baz}``. Instead string manipulation is done by the :doc:`string <cmds/string>` builtin.
 
 For example, to replace "bar" with "baz"::
 
@@ -191,7 +191,7 @@ just use::
 
   command | source
 
-as fish's :ref:`source <cmd-source>` can read from stdin.
+as fish's :doc:`source <cmds/source>` can read from stdin.
 
 Heredocs
 --------
@@ -275,7 +275,7 @@ Fish has a POSIX-compatible ``test`` or ``[`` builtin. There is no ``[[`` and ``
 Arithmetic Expansion
 --------------------
 
-Fish does not have ``$((i+1))`` arithmetic expansion, computation is handled by :ref:`math <cmd-math>`::
+Fish does not have ``$((i+1))`` arithmetic expansion, computation is handled by :doc:`math <cmds/math>`::
 
   math $i + 1
 
@@ -298,7 +298,7 @@ Both ``*`` and ``x`` are valid ways to spell multiplication, but ``*`` needs to
 Prompts
 -------
 
-Fish does not use the ``$PS1``, ``$PS2`` and so on variables. Instead the prompt is the output of the :ref:`fish_prompt <cmd-fish_prompt>` function, plus the :ref:`fish_mode_prompt <cmd-fish_mode_prompt>` function if vi-mode is enabled and the :ref:`fish_right_prompt <cmd-fish_right_prompt>` function for the right prompt.
+Fish does not use the ``$PS1``, ``$PS2`` and so on variables. Instead the prompt is the output of the :doc:`fish_prompt <cmds/fish_prompt>` function, plus the :doc:`fish_mode_prompt <cmds/fish_mode_prompt>` function if vi-mode is enabled and the :doc:`fish_right_prompt <cmds/fish_right_prompt>` function for the right prompt.
 
 As an example, here's a relatively simple bash prompt:
 
@@ -320,9 +320,9 @@ and a rough fish equivalent::
 
 This shows a few differences:
 
-- Fish provides :ref:`set_color <cmd-set_color>` to color text. It can use the 16 named colors and also RGB sequences (so you could also use ``set_color 5555FF``)
-- Instead of introducing specific escapes like ``\h`` for the hostname, the prompt is simply a function. To achieve the effect of ``\h``, fish provides helper functions like :ref:`prompt_hostname <cmd-prompt_hostname>`, which prints a shortened version of the hostname.
-- Fish offers other helper functions for adding things to the prompt, like :ref:`fish_vcs_prompt <cmd-fish_vcs_prompt>` for adding a display for common version control systems (git, mercurial, svn), and :ref:`prompt_pwd <cmd-prompt_pwd>` for showing a shortened ``$PWD`` (the user's home directory becomes ``~`` and any path component is shortened).
+- Fish provides :doc:`set_color <cmds/set_color>` to color text. It can use the 16 named colors and also RGB sequences (so you could also use ``set_color 5555FF``)
+- Instead of introducing specific escapes like ``\h`` for the hostname, the prompt is simply a function. To achieve the effect of ``\h``, fish provides helper functions like :doc:`prompt_hostname <cmds/prompt_hostname>`, which prints a shortened version of the hostname.
+- Fish offers other helper functions for adding things to the prompt, like :doc:`fish_vcs_prompt <cmds/fish_vcs_prompt>` for adding a display for common version control systems (git, mercurial, svn), and :doc:`prompt_pwd <cmds/prompt_pwd>` for showing a shortened ``$PWD`` (the user's home directory becomes ``~`` and any path component is shortened).
 
 The default prompt is reasonably full-featured and its code can be read via ``type fish_prompt``.
 
@@ -439,11 +439,11 @@ Builtins and other commands
 
 By now it has become apparent that fish puts much more of a focus on its builtins and external commands rather than its syntax. So here are some helpful builtins and their rough equivalent in bash:
 
-- :ref:`string <cmd-string>` - this replaces most of the string transformation (``${i%foo}`` et al) and can also be used instead of ``grep`` and ``sed`` and such.
-- :ref:`math <cmd-math>` - this replaces ``$((i + 1))`` arithmetic and can also do floats and some simple functions (sine and friends).
-- :ref:`argparse <cmd-argparse>` - this can handle a script's option parsing, for which bash would probably use ``getopt`` (zsh provides ``zparseopts``).
-- :ref:`count <cmd-count>` can be used to count things and therefore replaces ``$#`` and can be used instead of ``wc``.
-- :ref:`status <cmd-status>` provides information about the shell status, e.g. if it's interactive or what the current linenumber is. This replaces ``$-`` and ``$BASH_LINENO`` and other variables.
+- :doc:`string <cmds/string>` - this replaces most of the string transformation (``${i%foo}`` et al) and can also be used instead of ``grep`` and ``sed`` and such.
+- :doc:`math <cmds/math>` - this replaces ``$((i + 1))`` arithmetic and can also do floats and some simple functions (sine and friends).
+- :doc:`argparse <cmds/argparse>` - this can handle a script's option parsing, for which bash would probably use ``getopt`` (zsh provides ``zparseopts``).
+- :doc:`count <cmds/count>` can be used to count things and therefore replaces ``$#`` and can be used instead of ``wc``.
+- :doc:`status <cmds/status>` provides information about the shell status, e.g. if it's interactive or what the current linenumber is. This replaces ``$-`` and ``$BASH_LINENO`` and other variables.
 
 - ``seq(1)`` can be used as a replacement for ``{1..10}`` range expansion. If your OS doesn't ship a ``seq`` fish includes a replacement function.
 
@@ -452,5 +452,5 @@ Other facilities
 
 Bash has ``set -x`` or ``set -o xtrace`` to print all commands that are being executed. In fish, this would be enabled by setting :envvar:`fish_trace`.
 
-Or, if your intention is to *profile* how long each line of a script takes, you can use ``fish --profile`` - see the :ref:`page for the fish command <cmd-fish>`.
+Or, if your intention is to *profile* how long each line of a script takes, you can use ``fish --profile`` - see the :doc:`page for the fish command <cmds/fish>`.