Extend the `NounVerbConfusion` linters to work with plural vs 3rd person singular present tense

**What problem does this solve?**

As well as confusing things like "breath" and "breathe" it turns out people confuse inflected forms, which can also be classified in this exact same mistake, but won't fit the linters' current patterns:

**Examples**
- the harper-ls-aarch64-unknown-linux-gnu binary on my machine **weights** 48M, which is a tad enormous for a command-line utility

**Component**
- [x] Core engine
- [ ] Plugin/Extension
- [ ] Other: _____

Start by locating the NounVerbConfusion linters in the core engine and inspect how their current patterns handle forms such as “breath” and “breathe.” Reproduce the reported “weights” example, then verify that plural and third-person singular present-tense forms are classified by the same linters without breaking existing cases.

Written by the indexing model from the issue text.