Add error for trailing angle brackets.

This commit adds a error (and accompanying machine applicable
suggestion) for trailing angle brackets on function calls with a
turbofish.

src/test/ui/issues/issue-54521-1.rs

@@ -0,0 +1,16 @@
+// compile-pass
+
+// This test checks that the `remove extra angle brackets` error doesn't happen for some
+// potential edge-cases..
+
+struct X {
+    len: u32,
+}
+
+fn main() {
+    let x = X { len: 3 };
+
+    let _ = x.len > (3);
+
+    let _ = x.len >> (3);
+}

src/test/ui/issues/issue-54521.fixed

@@ -0,0 +1,22 @@
+// run-rustfix
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+//                                                        ^^ help: remove extra angle brackets
+// ```
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>();
+    //~^ ERROR unmatched angle bracket
+}

src/test/ui/issues/issue-54521.rs

@@ -0,0 +1,22 @@
+// run-rustfix
+
+// This test checks that the following error is emitted and the suggestion works:
+//
+// ```
+// let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+//                                                        ^^ help: remove extra angle brackets
+// ```
+
+fn main() {
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+    //~^ ERROR unmatched angle bracket
+
+    let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>();
+    //~^ ERROR unmatched angle bracket
+}

src/test/ui/issues/issue-54521.stderr

@@ -0,0 +1,26 @@
+error: unmatched angle bracket
+  --> $DIR/issue-54521.rs:11:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>>();
+   |                                                            ^^^^ help: remove extra angle bracket
+
+error: unmatched angle bracket
+  --> $DIR/issue-54521.rs:14:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>>();
+   |                                                            ^^^ help: remove extra angle bracket
+
+error: unmatched angle bracket
+  --> $DIR/issue-54521.rs:17:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>>();
+   |                                                            ^^ help: remove extra angle bracket
+
+error: unmatched angle bracket
+  --> $DIR/issue-54521.rs:20:60
+   |
+LL |     let _ = vec![1, 2, 3].into_iter().collect::<Vec<usize>>>();
+   |                                                            ^ help: remove extra angle bracket
+
+error: aborting due to 4 previous errors
+