doc: typeset long options with argument as literal

We previously reformatted '--option' to `--option`. This patch reformats
'--option <arg>' to `--option <arg>`. Obtained with:

  perl -pi -e "s/'(--[a-z][a-z=<>-]* <[^>]*>)'/\`\$1\`/g" *.txt

Signed-off-by: Matthieu Moy <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: moy

Documentation/git-config.txt

@@ -47,12 +47,12 @@ checks or transformations are performed on the value.
 
 When reading, the values are read from the system, global and
 repository local configuration files by default, and options
-`--system`, `--global`, `--local` and '--file <filename>' can be
+`--system`, `--global`, `--local` and `--file <filename>` can be
 used to tell the command to read from only that location (see <<FILES>>).
 
 When writing, the new value is written to the repository local
 configuration file by default, and options `--system`, `--global`,
-'--file <filename>' can be used to tell the command to write to
+`--file <filename>` can be used to tell the command to write to
 that location (you can say `--local` but that is the default).
 
 This command will fail with non-zero status upon error.  Some exit