Add verb past form only helpers

[impetus82]

Summary

• add DictWordMetadata::is_verb_simple_past_only
• add DictWordMetadata::is_verb_past_participle_only
• expose both helpers through TokenKind
• cover irregular-only forms (ate, eaten) and ambiguous/regular forms (thought, walked)

Fixes #3372.

Testing

• cargo fmt --package harper-core
• cargo test -p harper-core past_only --lib
• cargo test -p harper-core participle_only --lib
• cargo test -p harper-core neither_past_form_only --lib
• git diff --check

[hippietrail]

It looks good to me. Your implementation was quite different from the mass noun one so I asked two AIs to compare them since I didn't trust my own Rust-foo.

Your test cases gave me an idea for a third you method you could trivially add that complements these.

[hippietrail]

Hey you know what would be even better, adding an is_verb_regular_past_form that does exactly this.

[impetus82]

Thanks for the suggestion. I added is_verb_regular_past_form alongside the existing helpers, delegated it through TokenKind, and added coverage for walked plus irregular past forms (ate, eaten, thought).

Local checks run:

• cargo fmt --package harper-core
• cargo test -p harper-core regular_past --lib
• cargo test -p harper-core past_only --lib
• cargo test -p harper-core participle_only --lib
• git diff --check

[hippietrail]

Actually I have a hunch that ::PAST might be unreliable. I think a more explicit way would be more trustworthy:

            v.verb_forms
                .is_some_and(|vf| vf.contains(VerbFormFlags::PRETERITE)
                               && vf.contains(VerbFormFlags::PAST_PARTICIPLE))

[impetus82]

Thanks, updated it to use the explicit PRETERITE + PAST_PARTICIPLE check instead of relying on PAST. I also adjusted the regular-past tests around thought and kept the distinct-form checks for ate, eaten, and walked.

Local checks run:

• cargo fmt --package harper-core
• cargo test -p harper-core regular_past --lib
• cargo test -p harper-core past_only --lib
• cargo test -p harper-core participle_only --lib
• git diff --check

[elijah-potter]

This looks good to me too. Thanks!