fix rustdoc warning

Author: beepster4096

src/thread.rs

@@ -358,7 +358,7 @@ impl<'mir, 'tcx: 'mir> ThreadManager<'mir, 'tcx> {
     /// `allow_terminated_joined` allows detaching joined threads that have already terminated.
     /// This matches Windows's behavior for `CloseHandle`.
     ///
-    /// See https://docs.microsoft.com/en-us/windows/win32/procthread/thread-handles-and-identifiers:
+    /// See <https://docs.microsoft.com/en-us/windows/win32/procthread/thread-handles-and-identifiers>:
     /// > The handle is valid until closed, even after the thread it represents has been terminated.
     fn detach_thread(&mut self, id: ThreadId, allow_terminated_joined: bool) -> InterpResult<'tcx> {
         trace!("detaching {:?}", id);