doc: module-signing.rst: Fix reST formatting

Move the _if_ outside the verbatim string.

Make key ring name as a verbatim string.

Signed-off-by: Philipp Hahn <hahn@univention.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/admin-guide/module-signing.rst b/Documentation/admin-guide/module-signing.rst
index 62e389f..f8b5841 100644
--- a/Documentation/admin-guide/module-signing.rst
+++ b/Documentation/admin-guide/module-signing.rst
@@ -204,8 +204,8 @@
 	keyctl padd asymmetric "" 0x223c7853 <my_public_key.x509
 
 Note, however, that the kernel will only permit keys to be added to
-``.builtin_trusted_keys _if_`` the new key's X.509 wrapper is validly signed by a key
-that is already resident in the .builtin_trusted_keys at the time the key was added.
+``.builtin_trusted_keys`` **if** the new key's X.509 wrapper is validly signed by a key
+that is already resident in the ``.builtin_trusted_keys`` at the time the key was added.
 
 
 ========================