Deprecate `filterTemplateSuggestions` in favor of `postProcessTemplateSuggestions`

[mschrage]

Proposal

Rename filterTemplateSuggestions to postProcessTemplateSuggestions. Type signature would remain the same.

Justification

filterTemplateSuggestions is a misnomer. The function may be used to add additional suggestions, or modify the the list of suggestions, rather than just filtering. In this regard, filterTemplateSuggestions is similar to postProcess and its name should reflect that.

[clo4]

Good opportunity to expose the tokens array too, necessary to hide suggestions if (for example) using a URL instead