git-{var,write-tree} docs: update mark-up of synopsis option descriptions

To unify mark-up used in our documentation to a newer convention,
started by 2229389 (doc: apply synopsis simplification on git-clone
and git-init, 2024-09-24), update the documentation for 'git var' and
'git write-tree' to

 * use [synopsis], not [verse] in the SYNOPSIS section
 * enclose `--option=<value>` in backquotes

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

Author: gitster

Documentation/git-var.adoc

@@ -8,8 +8,8 @@ git-var - Show a Git logical variable
 
 SYNOPSIS
 --------
-[verse]
-'git var' (-l | <variable>)
+[synopsis]
+git var (-l | <variable>)
 
 DESCRIPTION
 -----------
@@ -18,7 +18,7 @@ no value.
 
 OPTIONS
 -------
--l::
+`-l`::
 	Display the logical variables. In addition, all the
 	variables of the Git configuration file .git/config are listed
 	as well. (However, the configuration variables listing functionality

Documentation/git-write-tree.adoc

@@ -8,8 +8,8 @@ git-write-tree - Create a tree object from the current index
 
 SYNOPSIS
 --------
-[verse]
-'git write-tree' [--missing-ok] [--prefix=<prefix>/]
+[synopsis]
+git write-tree [--missing-ok] [--prefix=<prefix>/]
 
 DESCRIPTION
 -----------
@@ -18,23 +18,23 @@ tree object is printed to standard output.
 
 The index must be in a fully merged state.
 
-Conceptually, 'git write-tree' sync()s the current index contents
+Conceptually, `git write-tree` sync()s the current index contents
 into a set of tree files.
 In order to have that match what is actually in your directory right
-now, you need to have done a 'git update-index' phase before you did the
-'git write-tree'.
+now, you need to have done a `git update-index` phase before you did the
+`git write-tree`.
 
 
 OPTIONS
 -------
---missing-ok::
-	Normally 'git write-tree' ensures that the objects referenced by the
+`--missing-ok`::
+	Normally `git write-tree` ensures that the objects referenced by the
 	directory exist in the object database.  This option disables this
 	check.
 
---prefix=<prefix>/::
+`--prefix=<prefix>/`::
 	Writes a tree object that represents a subdirectory
-	`<prefix>`.  This can be used to write the tree object
+	_<prefix>_.  This can be used to write the tree object
 	for a subproject that is in the named subdirectory.
 
 GIT