Update contrib guideline for lc in ID metadata

Author: Bob Furu

contributing_to_docs/doc_guidelines.adoc

@@ -34,7 +34,7 @@ include::modules/common-attributes.adoc[]                       <3>
 toc::[]                                                         <6>
 ----
 
-<1> A unique (within OpenShift docs) anchor id for this assembly. Example: cli-developer-commands
+<1> A unique (within OpenShift docs) anchor id for this assembly. Use lowercase. Example: cli-developer-commands
 <2> Human readable title (notice the '=' top-level header)
 <3> Includes attributes common to OpenShift docs.
 +
@@ -69,7 +69,7 @@ Every module should be placed in the modules folder and should contain the follo
 ----
 
 <1> List of assemblies in which this module is included.
-<2> A module anchor with {context} that must match the module's file name.
+<2> A module anchor with {context} that must be lowercase and must match the module's file name.
 <3> Human readable title. To ensure consistency in the results of the
 leveloffset values in include statements, you must use a level one heading
 ( = ) for the module title.