doc: convert git-mergetool manpage to new synopsis style

- Switch the synopsis to a synopsis block which will automatically
  format placeholders in italics and keywords in monospace
- Use _<placeholder>_ instead of <placeholder> in the description
- Use `backticks` for keywords and more complex option
descriptions. The new rendering engine will apply synopsis rules to
these spans.

Signed-off-by: Jean-Noël Avila <jn.avila@free.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-mergetool.adoc

@@ -7,95 +7,95 @@ git-mergetool - Run merge conflict resolution tools to resolve merge conflicts
 
 SYNOPSIS
 --------
-[verse]
-'git mergetool' [--tool=<tool>] [-y | --[no-]prompt] [<file>...]
+[synopsis]
+git mergetool [--tool=<tool>] [-y | --[no-]prompt] [<file>...]
 
 DESCRIPTION
 -----------
 
 Use `git mergetool` to run one of several merge utilities to resolve
-merge conflicts.  It is typically run after 'git merge'.
+merge conflicts.  It is typically run after `git merge`.
 
 If one or more <file> parameters are given, the merge tool program will
 be run to resolve differences in each file (skipping those without
 conflicts).  Specifying a directory will include all unresolved files in
-that path.  If no <file> names are specified, 'git mergetool' will run
+that path.  If no _<file>_ names are specified, `git mergetool` will run
 the merge tool program on every file with merge conflicts.
 
 OPTIONS
 -------
--t <tool>::
---tool=<tool>::
-	Use the merge resolution program specified by <tool>.
-	Valid values include emerge, gvimdiff, kdiff3,
-	meld, vimdiff, and tortoisemerge. Run `git mergetool --tool-help`
-	for the list of valid <tool> settings.
+`-t <tool>`::
+`--tool=<tool>`::
+	Use the merge resolution program specified by _<tool>_.
+	Valid values include `emerge`, `gvimdiff`, `kdiff3`,
+	`meld`, `vimdiff`, and `tortoisemerge`. Run `git mergetool --tool-help`
+	for the list of valid _<tool>_ settings.
 +
-If a merge resolution program is not specified, 'git mergetool'
+If a merge resolution program is not specified, `git mergetool`
 will use the configuration variable `merge.tool`.  If the
-configuration variable `merge.tool` is not set, 'git mergetool'
+configuration variable `merge.tool` is not set, `git mergetool`
 will pick a suitable default.
 +
 You can explicitly provide a full path to the tool by setting the
 configuration variable `mergetool.<tool>.path`. For example, you
 can configure the absolute path to kdiff3 by setting
-`mergetool.kdiff3.path`. Otherwise, 'git mergetool' assumes the
-tool is available in PATH.
+`mergetool.kdiff3.path`. Otherwise, `git mergetool` assumes the
+tool is available in `$PATH`.
 +
 Instead of running one of the known merge tool programs,
-'git mergetool' can be customized to run an alternative program
+`git mergetool` can be customized to run an alternative program
 by specifying the command line to invoke in a configuration
 variable `mergetool.<tool>.cmd`.
 +
-When 'git mergetool' is invoked with this tool (either through the
+When `git mergetool` is invoked with this tool (either through the
 `-t` or `--tool` option or the `merge.tool` configuration
-variable), the configured command line will be invoked with `$BASE`
+variable), the configured command line will be invoked with `BASE`
 set to the name of a temporary file containing the common base for
-the merge, if available; `$LOCAL` set to the name of a temporary
+the merge, if available; `LOCAL` set to the name of a temporary
 file containing the contents of the file on the current branch;
-`$REMOTE` set to the name of a temporary file containing the
-contents of the file to be merged, and `$MERGED` set to the name
+`REMOTE` set to the name of a temporary file containing the
+contents of the file to be merged, and `MERGED` set to the name
 of the file to which the merge tool should write the result of the
 merge resolution.
 +
 If the custom merge tool correctly indicates the success of a
 merge resolution with its exit code, then the configuration
 variable `mergetool.<tool>.trustExitCode` can be set to `true`.
-Otherwise, 'git mergetool' will prompt the user to indicate the
+Otherwise, `git mergetool` will prompt the user to indicate the
 success of the resolution after the custom tool has exited.
 
---tool-help::
+`--tool-help`::
 	Print a list of merge tools that may be used with `--tool`.
 
--y::
---no-prompt::
+`-y`::
+`--no-prompt`::
 	Don't prompt before each invocation of the merge resolution
 	program.
 	This is the default if the merge resolution program is
 	explicitly specified with the `--tool` option or with the
 	`merge.tool` configuration variable.
 
---prompt::
+`--prompt`::
 	Prompt before each invocation of the merge resolution program
 	to give the user a chance to skip the path.
 
--g::
---gui::
-	When 'git-mergetool' is invoked with the `-g` or `--gui` option,
+`-g`::
+`--gui`::
+	When `git-mergetool` is invoked with the `-g` or `--gui` option,
 	the default merge tool will be read from the configured
 	`merge.guitool` variable instead of `merge.tool`. If
 	`merge.guitool` is not set, we will fallback to the tool
 	configured under `merge.tool`. This may be autoselected using
 	the configuration variable `mergetool.guiDefault`.
 
---no-gui::
+`--no-gui`::
 	This overrides a previous `-g` or `--gui` setting or
 	`mergetool.guiDefault` configuration and reads the default merge
 	tool from the configured `merge.tool` variable.
 
--O<orderfile>::
+`-O<orderfile>`::
 	Process files in the order specified in the
-	<orderfile>, which has one shell glob pattern per line.
+	_<orderfile>_, which has one shell glob pattern per line.
 	This overrides the `diff.orderFile` configuration variable
 	(see linkgit:git-config[1]).  To cancel `diff.orderFile`,
 	use `-O/dev/null`.