Add the vcs prompts to sphinx docs

sphinx_doc_src/cmds/fish_hg_prompt.rst

@@ -0,0 +1,47 @@
+fish_hg_prompt - output mercurial information for use in a prompt
+=================================================================
+
+Description
+-----------
+
+The fish_hg_prompt function can be used to display information about the current mercurial repository, if any.
+
+For obvious reasons, it requires having hg installed.
+
+There are numerous configuration options:
+
+- $fish_color_hg_clean, $fish_color_hg_modified and $fish_color_hg_dirty: The color to use when the repo has the respective status
+
+Some colors for status symbols:
+
+- $fish_color_hg_added
+- $fish_color_hg_renamed
+- $fish_color_hg_copied
+- $fish_color_hg_deleted
+- $fish_color_hg_untracked
+- $fish_color_hg_unmerged
+
+And the status symbols themselves:
+
+- $fish_prompt_hg_status_added, default '✚'
+- $fish_prompt_hg_status_modified, default '*'
+- $fish_prompt_hg_status_copied, default '⇒'
+- $fish_prompt_hg_status_deleted, default '✖'
+- $fish_prompt_hg_status_untracked, default '?'
+- $fish_prompt_hg_status_unmerged, default '!'
+
+And $fish_prompt_hg_status_order, which can be used to change the order the status symbols appear in. It defaults to ``added modified copied deleted untracked unmerged``.
+
+See also fish_vcs_prompt, which will call all supported vcs-prompt functions, including git, hg and svn.
+
+Example
+-------
+
+A simple prompt that displays hg info::
+
+    function fish_prompt
+        ...
+        printf '%s %s$' $PWD (fish_hg_prompt)
+    end
+
+