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).

cameraserver/src/test/native/cpp/main.cpp

@@ -2,4 +2,6 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
-int main() { return 0; }
+int main() {
+  return 0;
+}