Correctly mark the ending span of a match arm

Closes #74050

r? @matthewjasper

src/test/ui/match/issue-74050-end-span.rs

@@ -0,0 +1,13 @@
+fn main() {
+    let mut args = std::env::args_os();
+    let _arg = match args.next() {
+        Some(arg) => {
+            match arg.to_str() {
+                //~^ ERROR `arg` does not live long enough
+                Some(s) => s,
+                None => return,
+            }
+        }
+        None => return,
+    };
+}

src/test/ui/match/issue-74050-end-span.stderr

@@ -0,0 +1,15 @@
+error[E0597]: `arg` does not live long enough
+  --> $DIR/issue-74050-end-span.rs:5:19
+   |
+LL |     let _arg = match args.next() {
+   |         ---- borrow later stored here
+LL |         Some(arg) => {
+LL |             match arg.to_str() {
+   |                   ^^^ borrowed value does not live long enough
+...
+LL |         }
+   |         - `arg` dropped here while still borrowed
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0597`.