builtin break/continue: support -h/--help argument

These are not generic builtins because we check whether they're inside
a loop. There's no reason to not support "break -h" when we support
"if -h" etc.; do that.

doc_src/cmds/break.rst

@@ -19,7 +19,7 @@ Description
 
 ``break`` halts a currently running loop (*LOOP_CONSTRUCT*), such as a :doc:`for <for>` or :doc:`while <while>` loop. It is usually added inside of a conditional block such as an :doc:`if <if>` block.
 
-There are no parameters for ``break``.
+The **-h** or **--help** option displays help about using this command.
 
 Example
 -------

doc_src/cmds/continue.rst

@@ -15,6 +15,8 @@ Description
 
 ``continue`` skips the remainder of the current iteration of the current inner loop, such as a :doc:`for <for>` loop or a :doc:`while <while>` loop. It is usually added inside of a conditional block such as an :doc:`if <if>` statement or a :doc:`switch <switch>` statement.
 
+The **-h** or **--help** option displays help about using this command.
+
 Example
 -------
 

src/builtins/shared.rs

@@ -978,6 +978,13 @@ fn builtin_break_continue(
     let is_break = argv[0] == "break";
     let argc = argv.len();
 
+    let opts = HelpOnlyCmdOpts::parse(argv, parser, streams)?;
+
+    if opts.print_help {
+        builtin_print_help(parser, streams, argv[0]);
+        return Ok(SUCCESS);
+    }
+
     if argc != 1 {
         let error_message = wgettext_fmt!(BUILTIN_ERR_UNKNOWN, argv[0], argv[1]);
         builtin_print_help_error(parser, streams, argv[0], &error_message);

tests/checks/basic.fish

@@ -442,6 +442,15 @@ eval continue
 #CHECKERR: Error-message: continue: Not inside of loop
 #CHECKERR: Documentation for continue
 
+break -h
+#CHECKERR: Documentation for break
+break --help
+#CHECKERR: Documentation for break
+$dyn_break -h
+#CHECKERR: Documentation for break
+continue -h
+#CHECKERR: Documentation for continue
+
 # Test implicit cd. This should do nothing.
 ./