mesonlib: add rsplit and and maxsplit

Since string has a maxsplit as well, we should implement that for
polymorphism

mesonbuild/mesonlib/universal.py

@@ -422,8 +422,11 @@ class File(HoldableObject):
     def endswith(self, ending: str) -> bool:
         return self.fname.endswith(ending)
 
-    def split(self, s: str) -> T.List[str]:
-        return self.fname.split(s)
+    def split(self, s: str, maxsplit: int = -1) -> T.List[str]:
+        return self.fname.split(s, maxsplit=maxsplit)
+
+    def rsplit(self, s: str, maxsplit: int = -1) -> T.List[str]:
+        return self.fname.rsplit(s, maxsplit=maxsplit)
 
     def __eq__(self, other: object) -> bool:
         if not isinstance(other, File):