Add braces to C++ single-line loops and conditionals (NFC) (#2973)

This makes code easier to read and more consistent between C++ and Java.
Also update clang-format settings to always add a line break (even if no braces are used).

simulation/halsim_ws_server/src/test/native/cpp/WebServerClientTest.cpp

@@ -154,6 +154,8 @@ void WebServerClientTest::SendMessage(const wpi::json& msg) {
   });
 }
 
-const wpi::json& WebServerClientTest::GetLastMessage() { return m_json; }
+const wpi::json& WebServerClientTest::GetLastMessage() {
+  return m_json;
+}
 
 }  // namespace wpilibws