Heuristic 'did this edit change a type' filters need removed-text checks

When an editor feature caches LSP-derived type information (for example enum member values from hover) and invalidates it only when an edit 'may change a type', a heuristic that inspects just the inserted text or the post-edit line misses common cases. Examples: a member line inside a multi-line typedef (no 'typedef'/'enum' keyword on that line); a backspace that deletes a type name, so only the removed text mentions it; a type never read before; parameters inside a multi-line #( ... ). The result is stale names forever. A reviewer found these by calling the predicate directly with five one-line cases. Safer designs: also mark the cache stale on save, on the server's recompile, and on data reload, which is cheap when reads are background and debounced. Add the missed lines as positive unit cases.