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/Vector3.hpp

@@ -14,7 +14,6 @@ namespace godot {
 class Basis;
 
 struct Vector3 {
-
 	enum Axis {
 		AXIS_X,
 		AXIS_Y,
@@ -305,7 +304,6 @@ inline Vector3 operator*(real_t p_scalar, const Vector3 &p_vec) {
 }
 
 inline Vector3 vec3_cross(const Vector3 &p_a, const Vector3 &p_b) {
-
 	return p_a.cross(p_b);
 }