Add descriptions for cat APIs

[lcawl]

This PR pulls descriptions from these docs:

• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-alias.html
• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-allocation.html
• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-component-templates.html
• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-count.html
• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-fielddata.html
• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-health.html
• https://www.elastic.co/guide/en/elasticsearch/reference/master/cat-indices.html

[sethmlarson]

Thanks Lisa! Can you open a separate issue for the CatCommonQueryParameters not getting picked up by validation-errors?

[sethmlarson]

@lcawl Also can you resolve the merge conflict and rebuild with make contrib?

[lcawl]

Thanks Lisa! Can you open a separate issue for the CatCommonQueryParameters not getting picked up by validation-errors?

Done! I created #2136

[github-actions]

Following you can find the validation results for the APIs you have changed.

API	Status	Request	Response
cat.aliases	🟢	24/24	24/24
cat.allocation	🟢	10/10	10/10
cat.component_templates	⚪	Missing test	Missing test
cat.count	🟢	9/9	9/9
cat.fielddata	🟢	6/6	6/6
cat.health	🟢	5/5	5/5
cat.indices	🟢	33/33	32/32
cat.ml_data_frame_analytics	🟢	5/5	5/5

You can validate these APIs yourself by using the make validate target.