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

test/testrendercopyex.c

@@ -22,7 +22,8 @@
 
 static SDLTest_CommonState *state;
 
-typedef struct {
+typedef struct
+{
     SDL_Window *window;
     SDL_Renderer *renderer;
     SDL_Texture *background;
@@ -42,13 +43,12 @@ quit(int rc)
     exit(rc);
 }
 
-void
-Draw(DrawState *s)
+void Draw(DrawState *s)
 {
     SDL_Rect viewport;
     SDL_Texture *target;
-    SDL_Point *center=NULL;
-    SDL_Point origin = {0,0};
+    SDL_Point *center = NULL;
+    SDL_Point origin = { 0, 0 };
 
     SDL_RenderGetViewport(s->renderer, &viewport);
 
@@ -108,8 +108,7 @@ void loop()
 #endif
 }
 
-int
-main(int argc, char *argv[])
+int main(int argc, char *argv[])
 {
     int i;
     int frames;
@@ -156,12 +155,12 @@ main(int argc, char *argv[])
     while (!done) {
         ++frames;
         loop();
-        }
+    }
 #endif
     /* Print out some timing information */
     now = SDL_GetTicks();
     if (now > then) {
-        double fps = ((double) frames * 1000) / (now - then);
+        double fps = ((double)frames * 1000) / (now - then);
         SDL_Log("%2.2f frames per second\n", fps);
     }