[ty] Add comprehensive hover.md mdtest (partial)
Add hover.md with examples of hover assertions across different
expression types. Some tests still need arrow alignment fixes, but
many sections are passing including basic literals, function definitions,
comprehensions, and the simple hover test file.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
