doc:process: add links where missing

Some documents are refering to others without links. With this
patch I add those missing links.

This patch affects only documents under process/ and labels where
necessary.

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
diff --git a/Documentation/process/howto.rst b/Documentation/process/howto.rst
index a4a9f9e..58b2f46 100644
--- a/Documentation/process/howto.rst
+++ b/Documentation/process/howto.rst
@@ -298,9 +298,9 @@
 security-related problem, instead, can cause a release to happen almost
 instantly.
 
-The file Documentation/process/stable-kernel-rules.rst in the kernel tree
-documents what kinds of changes are acceptable for the -stable tree, and
-how the release process works.
+The file :ref:`Documentation/process/stable-kernel-rules.rst <stable_kernel_rules>`
+in the kernel tree documents what kinds of changes are acceptable for
+the -stable tree, and how the release process works.
 
 4.x -git patches
 ~~~~~~~~~~~~~~~~
@@ -360,7 +360,8 @@
 
 	https://bugzilla.kernel.org/page.cgi?id=faq.html
 
-The file admin-guide/reporting-bugs.rst in the main kernel source directory has a good
+The file :ref:`admin-guide/reporting-bugs.rst <reportingbugs>`
+in the main kernel source directory has a good
 template for how to report a possible kernel bug, and details what kind
 of information is needed by the kernel developers to help track down the
 problem.
@@ -426,7 +427,7 @@
 writing at the top of the mail.
 
 If you add patches to your mail, make sure they are plain readable text
-as stated in Documentation/process/submitting-patches.rst.
+as stated in :ref:`Documentation/process/submitting-patches.rst <submittingpatches>`.
 Kernel developers don't want to deal with
 attachments or compressed patches; they may want to comment on
 individual lines of your patch, which works only that way. Make sure you