[clang] [libclang/python] Fix bug in `SourceRange.__contains__`, add tests (PR #101802)

[Vlad Serebrennikov via cfe-commits]

================
@@ -386,6 +386,10 @@ def __contains__(self, other):
         # same file, in between lines
         if self.start.line < other.line < self.end.line:
             return True
+        # between columns in one-liner range
+        elif self.start.line == other.line == self.end.line:
----------------
Endilll wrote:

Is there a reason you implemented _less-or-equals_ operator, and not _less_? `operator<` + `operator==` is sort of a canonical pair of operators to establish ordering, and it would match `SourceLocation` in C++.

https://github.com/llvm/llvm-project/pull/101802