Previously, submatches were handled simply by searching in placeholders
for more matches. That only works if we search all nodes in the tree
recursively. In a subsequent commit, I intend to make search not always
be recursive recursive. This commit prepares for that by finding all
matches, even if they overlap, then nesting them and removing
overlapping matches.
The methods `edits_for_file` and `find_matches_in_file` are replaced with just `edits` and `matches`. This simplifies the API a bit, but more importantly it makes it possible in a subsequent commit for SSR to decide to not search all files.
Also renamed find_matches to slow_scan_node to reflect that it's a slow
way to do things. Actually the name came from a later commit and
probably makes more sense once there's an alternative.
