doc: Misc syntax and spelling fixes

Tidying up a few Sphinx warnings that had built-up over time.
None of these are critical but it cleans up the Sphinx output.

At the same time, fixing some spelling errors that were detected.

Change-Id: I38209e235481eed287f8008c6de9dedd6b12ab2e
Signed-off-by: Paul Beesley <paul.beesley@arm.com>
diff --git a/docs/process/coding-guidelines.rst b/docs/process/coding-guidelines.rst
index a53da77..cb8b892 100644
--- a/docs/process/coding-guidelines.rst
+++ b/docs/process/coding-guidelines.rst
@@ -23,8 +23,8 @@
 
 - ``**WARNING: Use of volatile is usually wrong``: see
   `Why the “volatile” type class should not be used`_ . Although this document
-  contains some very useful information, there are several legimate uses of the
-  volatile keyword within the TF codebase.
+  contains some very useful information, there are several legitimate uses of
+  the volatile keyword within the TF codebase.
 
 Headers and inclusion
 ---------------------