Mark Synonyms API as stable

[kderusso]

No description provided.

[github-actions]

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

API	Status	Request	Response
synonyms.delete_synonym_rule	⚪	Missing test	Missing test
synonyms.delete_synonym	⚪	Missing test	Missing test
synonyms.get_synonym_rule	⚪	Missing test	Missing test
synonyms.get_synonym	⚪	Missing test	Missing test
synonyms.get_synonyms_sets	⚪	Missing test	Missing test
synonyms.put_synonym_rule	⚪	Missing test	Missing test
synonyms.put_synonym	⚪	Missing test	Missing test

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

[Mikep86]

LGTM

[pquentin]

Thanks! In what version do they become stable? (Wondering if this should be backported to the 8.12 branch.)

[kderusso]

Thanks! In what version do they become stable? (Wondering if this should be backported to the 8.12 branch.)
@pquentin This is planned for 8.13! Thanks for asking!

[codebrain]

Thanks! In what version do they become stable? (Wondering if this should be backported to the 8.12 branch.)

Marked as public in 8.10:
https://github.com/elastic/elasticsearch/pull/97962/files

Marked as stable in 8.13:
elastic/elasticsearch#103223

Please ensure online docs are updated too as they are showing the API is in beta (which is incorrect):

[pquentin]

The docs built from the main branch (that will become 8.13) are already correct: https://www.elastic.co/guide/en/elasticsearch/reference/master/synonyms-apis.html