ref-manual: render options in monospace to show quotes properly

It's important (at least for now) to mark up options with monospaced
font to highlight the difference between single and double quotes.

(From yocto-docs rev: 8d71ffdd3f354747dcade6de512355e8fa567728)

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Reviewed-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/devtool-reference.rst

@@ -78,7 +78,7 @@ has a number of sub-commands for each function. You can run
 
 As directed in the general help output, you can
 get more syntax on a specific command by providing the command name and
-using "--help"::
+using ``--help``::
 
    $ devtool add --help
    NOTE: Starting bitbake server...
@@ -471,7 +471,7 @@ Use the ``devtool build`` command to build your recipe. The
 
 When you use the ``devtool build`` command, you must supply the root
 name of the recipe (i.e. do not provide versions, paths, or extensions).
-You can use either the "-s" or the "--disable-parallel-make" options to
+You can use either the ``-s`` or the ``--disable-parallel-make`` options to
 disable parallel makes during the build. Here is an example::
 
    $ devtool build recipe