fix(extract): make _TsRangeIndex a real type alias

The alias was written as a quoted string, which makes it a `str` *value*
rather than a type. Type checkers reject it: mypy reports "Variable
_TsRangeIndex is not valid as a type" at both annotation sites, plus two
cascading errors where the tuple loses its type and the unpacking/indexing
in _ts_ranges_containing and _normalize_ts_import_types become untyped.

`typing.get_type_hints` happened to resolve it at runtime because it
evaluates the annotation string and then the alias string again, so nothing
failed in practice -- but that is an accident of double evaluation, not a
working alias.

Unquote the right-hand side. The module already has
`from __future__ import annotations`, so the annotations themselves need no
quoting either. No behavior change.

(cherry picked from commit d902820ccf)

graphify/extract.py

@@ -1363,13 +1363,14 @@ def _ts_type_argument_ranges(root: Any, *, call_only: bool) -> list[tuple[int, i
 
 
 # Sorted type-argument ranges prepared for lookup: (starts, spans, prefix_max_end).
-# See _ts_build_range_index.
-_TsRangeIndex = "tuple[list[int], list[tuple[int, int]], list[int]]"
+# See _ts_build_range_index. A real alias, not a string: quoting the right-hand
+# side would make this a `str` value, which type checkers reject as a type.
+_TsRangeIndex = tuple[list[int], list[tuple[int, int]], list[int]]
 
 
 def _ts_ranges_containing(
-    ranges: "_TsRangeIndex", offset: int
-) -> "list[tuple[int, int]]":
+    ranges: _TsRangeIndex, offset: int
+) -> list[tuple[int, int]]:
     """Return the ranges in ``ranges`` that contain ``offset``.
 
     Scanning the full range list for every match made
@@ -1397,7 +1398,7 @@ def _ts_ranges_containing(
     return hits
 
 
-def _ts_build_range_index(root: Any, *, call_only: bool) -> "_TsRangeIndex":
+def _ts_build_range_index(root: Any, *, call_only: bool) -> _TsRangeIndex:
     """Index :func:`_ts_type_argument_ranges` for :func:`_ts_ranges_containing`.
 
     Returns the ranges sorted by start, split into a bare ``starts`` list for