It's now consistent with other variables in that if the pattern
references self, only the `self` in scope where the rule is invoked will
be accepted. Since `self` doesn't work the same as other paths, this is
implemented by restricting the search to just the current function.
Prior to this change (since path resolution was implemented), having
self in a pattern would just result in no matches.
This differs from how this used to work before I removed it in that:
a) It's only one direction. Function calls in the pattern can match
method calls in the code, but not the other way around.
b) We now check that the function call in the pattern resolves to the
same function as the method call in the code.
The lack of (b) was the reason I felt the need to remove the feature
before.
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.
