Update clang-format to version 11

This is taken from the Godot repository, so formatting is similar. This
updates the style rules as well.

Also fix style in files to conform with this version.

include/core/Math.hpp

@@ -232,7 +232,6 @@ inline double stepify(double p_value, double p_step) {
 }
 
 inline unsigned int next_power_of_2(unsigned int x) {
-
 	if (x == 0)
 		return 0;