[PATCH] fs: porting.rst: use literal string to avoid warning

[Randy Dunlap <rdunlap@infradead.org>]

Avoid the docutils warning:

Documentation/filesystems/porting.rst:1417: WARNING: Inline emphasis start-string without end-string. [docutils]

by quoting the const pointer in literal quotation marks.
(Adding a space between the '*' and the '.' also works but it looks odd.)

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202609231806.ILZP6Fy0-lkp@intel.com/
Fixes: 025756ee7b47 ("fs: port mnt_idmap() and file_mnt_idmap() to const mnt_idmap")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
---
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: linux-fsdevel@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: linux-doc@vger.kernel.org

 Documentation/filesystems/porting.rst |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- linux-next-20260923.orig/Documentation/filesystems/porting.rst
+++ linux-next-20260923/Documentation/filesystems/porting.rst
@@ -1418,7 +1418,7 @@ All struct mnt_idmap pointers handed to
 ->create(), ->mkdir(), ->mknod(), ->symlink(), ->rename(), ->setattr(),
 ->getattr(), ->permission(), ->tmpfile(), ->get_acl(), ->set_acl() and
 ->fileattr_set() as well as the xattr ->set() handler and the vfs_*()
-helpers take a const struct mnt_idmap *. mnt_idmap() and file_mnt_idmap()
+helpers take a ``const struct mnt_idmap *``. mnt_idmap() and file_mnt_idmap()
 return one. The idmapping is immutable so nothing should have modified it
 anyway. References are taken and dropped via mnt_idmap_get() and
 mnt_idmap_put() as before, both accept a const pointer.