[syntax-errors] Irrefutable case pattern before final case (#16905)

Summary
--

Detects irrefutable `match` cases before the final case using a modified
version
of the existing `Pattern::is_irrefutable` method from the AST crate. The
modified method helps to retrieve a more precise diagnostic range to
match what
Python 3.13 shows in the REPL.

Test Plan
--

New inline tests, as well as some updates to existing tests that had
irrefutable
patterns before the last block.

crates/ruff_python_parser/resources/valid/statement/match.py

@@ -243,18 +243,21 @@ match x:
 match x:
     case a:
         ...
+match x:
     case a as b:
         ...
+match x:
     case 1 | 2 as two:
         ...
     case 1 + 3j as sum:
         ...
     case a.b as ab:
         ...
-    case _:
-        ...
     case _ as x:
         ...
+match x:
+    case _:
+        ...
 
 # PatternMatchSequence
 match x: