feat: adding prefixes to dictionary

[hippietrail]

Issues

Inspired by the second point in #2203

Description

Annotating prefixes in the dictionary and annotations.

Since many prefixes are not also words, this doesn't add any prefixes, it just annotates the ones that are already there due to also being words.
But I've added a comment for each prefix that is not also a word to dissuade contributors from adding them.

Adding them to the dictionary would cause them not to be flagged by the spellchecker.

If/when we need a way to handle all prefixes that would be best done with something like a SequenceExpr::WordSet in addition to an .is_prefix()

Knowing about prefixes will help modify the current MergeWords linter and/or MergeableWords expression, or add equivalent ones that would be able to deal with things like "re-read", "re read", "dis like", etc.

So far I've never seen the same mistake in the wild made with suffixes. Since I can't think of a need for suffix support yet, I've only added the barest skeleton of it in the DictWordMetadata.

Checklist

• I have performed a self-review of my own code
• I have added tests to cover my changes