config/alias.txt: change " and ' to `

Before, the documentation would mix " and ' for code and config
snippets. Change these instances to ` so that they are marked up in
monospace.

Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config/alias.txt

@@ -1,18 +1,18 @@
 alias.*::
 	Command aliases for the linkgit:git[1] command wrapper - e.g.
-	after defining "alias.last = cat-file commit HEAD", the invocation
-	"git last" is equivalent to "git cat-file commit HEAD". To avoid
+	after defining `alias.last = cat-file commit HEAD`, the invocation
+	`git last` is equivalent to `git cat-file commit HEAD`. To avoid
 	confusion and troubles with script usage, aliases that
 	hide existing Git commands are ignored. Arguments are split by
 	spaces, the usual shell quoting and escaping is supported.
 	A quote pair or a backslash can be used to quote them.
 +
 If the alias expansion is prefixed with an exclamation point,
 it will be treated as a shell command.  For example, defining
-"alias.new = !gitk --all --not ORIG_HEAD", the invocation
-"git new" is equivalent to running the shell command
-"gitk --all --not ORIG_HEAD".  Note that shell commands will be
+`alias.new = !gitk --all --not ORIG_HEAD`, the invocation
+`git new` is equivalent to running the shell command
+`gitk --all --not ORIG_HEAD`.  Note that shell commands will be
 executed from the top-level directory of a repository, which may
 not necessarily be the current directory.
-`GIT_PREFIX` is set as returned by running 'git rev-parse --show-prefix'
+`GIT_PREFIX` is set as returned by running `git rev-parse --show-prefix`
 from the original current directory. See linkgit:git-rev-parse[1].