Update for SDL3 coding style (#6717)

I updated .clang-format and ran clang-format 14 over the src and test directories to standardize the code base.

In general I let clang-format have it's way, and added markup to prevent formatting of code that would break or be completely unreadable if formatted.

The script I ran for the src directory is added as build-scripts/clang-format-src.sh

This fixes:
#6592
#6593
#6594

src/render/SDL_d3dmath.h

@@ -52,8 +52,10 @@ typedef struct
 
 typedef struct
 {
-    union {
-        struct {
+    union
+    {
+        struct
+        {
             float _11, _12, _13, _14;
             float _21, _22, _23, _24;
             float _31, _32, _33, _34;
@@ -63,7 +65,6 @@ typedef struct
     };
 } Float4X4;
 
-
 Float4X4 MatrixIdentity();
 Float4X4 MatrixMultiply(Float4X4 M1, Float4X4 M2);
 Float4X4 MatrixScaling(float x, float y, float z);