Introduce Synonym Suggestions

**What problem does this solve?**
Synonyms can help avoid repetition, improve user vocabulary, and are a truly powerful tool for authors.

Also, individuals who are neurodivergent (dyslexia, autism, etc.) can struggle with word recall, having the ability to write one word to find another would help them immensely. English learners can also benefit as wrong word choice is frequently one of the most common problem they face.

The BoringWords rule that is disabled by default would also become more powerful.

**Proposed Solution**
Double clicking on a correctly spelled word would open pop-up with synonyms.

**Examples**

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

**Additional Context**
https://www.grammarly.com/blog/grammar/synonyms/

Start by locating the core engine entry points that handle correctly spelled words and word selection. The issue does not name files or tests, so first map how a double-click could reach synonym lookup and a popup; done means a selected word presents useful synonyms without affecting existing spelling behavior.

Written by the indexing model from the issue text.