[ENHANCEMENT] Update auto-complete with new/updated terms

[jcscottiii]

There are two new terms that need to be added to the autocomplete:

• group:
• snapshot:

Additionally, I made a mistake with the earlier available_date term.

It now needs to be updated to have available_date:BROWSER: as the prefix before the date.

You can find out more about these terms in the examples: https://github.com/GoogleChrome/webstatus.dev/blob/main/antlr/FeatureSearch.md#simple-term-examples

https://github.com/GoogleChrome/webstatus.dev/blob/f407ba493abe9ae0a4a894b2b6949bf37de47115/antlr/FeatureSearch.md?plain=1#L50-L59