Add PICS Code support to generate_spec_xml.py (project-chip#41180)

* Add PICS Code support to generate_spec_xml.py
* Add and populate PICS Code column in spec_clusters.md

* Ignore acronyms in check spelling

* Fix spell check to ignore acronyms

* Add new line at the end of .spellcheck.yml

Author: AryaHassanli

.spellcheck.yml

@@ -61,6 +61,9 @@ matrix:
           # Ignore code markers
           - open: '<code>'
             close: '</code>'
+          # Ignore Acronyms
+          - open: '(?<![a-z])\b[A-Z]{2,}\b'
+            close: '\b'
 
       # converts markdown to HTML
       - pyspelling.filters.markdown: