New lint: unnecessary_semicolon (#14032)

This lint detects and removes the unnecessary semicolon after a `match`
or `if` statement returning `()`. It seems to be quite a common
"mistake", given the number of hits (88) we had in the Clippy sources
themselves.

The lint doesn't bother about loops, as `rustfmt` already removes the
extra semicolon. It doesn't handle blocks either, as an extra block
level, followed or not by a semicolon, is likely intentional.

I propose to put the lint in `pedantic`, as putting it in `style` seems
quite hazardous given the number of hits.

Note: there exists a `redundant-semicolon` lint in the compiler, but it
is an early lint and cannot check that the expression evaluates to `()`,
so it ignores the cases we're handling here.

----

changelog: [`unnecessary_semicolon`]: new lint

clippy_lints/src/methods/bytecount.rs

@@ -62,5 +62,5 @@ pub(super) fn check<'tcx>(
             ),
             applicability,
         );
-    };
+    }
 }

clippy_lints/src/methods/bytes_count_to_len.rs

@@ -32,5 +32,5 @@ pub(super) fn check<'tcx>(
             ),
             applicability,
         );
-    };
+    }
 }

clippy_lints/src/methods/bytes_nth.rs

@@ -46,5 +46,5 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, recv: &'tcx E
             format!("{receiver}.as_bytes().get({n}).copied()"),
             applicability,
         );
-    };
+    }
 }

clippy_lints/src/methods/cloned_instead_of_copied.rs

@@ -32,7 +32,7 @@ pub fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, span: Span,
         // &T where T: Copy
         ty::Ref(_, ty, _) if is_copy(cx, *ty) => {},
         _ => return,
-    };
+    }
     span_lint_and_sugg(
         cx,
         CLONED_INSTEAD_OF_COPIED,

clippy_lints/src/methods/err_expect.rs

@@ -37,7 +37,7 @@ pub(super) fn check(
             "expect_err".to_string(),
             Applicability::MachineApplicable,
         );
-    };
+    }
 }
 
 /// Given a `Result<T, E>` type, return its data (`T`).

clippy_lints/src/methods/expect_fun_call.rs

@@ -58,7 +58,7 @@ pub(super) fn check<'tcx>(
             if ty.is_str() && can_be_static_str(cx, arg) {
                 return false;
             }
-        };
+        }
         true
     }
 

clippy_lints/src/methods/iter_with_drain.rs

@@ -25,5 +25,5 @@ pub(super) fn check(cx: &LateContext<'_>, expr: &Expr<'_>, recv: &Expr<'_>, span
             "into_iter()".to_string(),
             Applicability::MaybeIncorrect,
         );
-    };
+    }
 }

clippy_lints/src/methods/path_ends_with_ext.rs

@@ -37,7 +37,7 @@ pub(super) fn check(
             let _ = write!(sugg, r#".extension().is_some_and(|ext| ext == "{path}")"#);
         } else {
             let _ = write!(sugg, r#".extension().map_or(false, |ext| ext == "{path}")"#);
-        };
+        }
 
         span_lint_and_sugg(
             cx,

clippy_lints/src/methods/unnecessary_iter_cloned.rs

@@ -87,7 +87,7 @@ pub fn check_for_loop_iter(
                 // skip lint
                 return true;
             }
-        };
+        }
 
         // the lint should not be executed if no violation happens
         let snippet = if let ExprKind::MethodCall(maybe_iter_method_name, collection, [], _) = receiver.kind