Style: Fix code format scripts compat with non-GNU Unices

It's too hard to get compatibility between GNU and BSD sed,
so let's just use perl oneliners.

And improve it to also remove trailing tabs, not just spaces.

modules/etc/image_etc.cpp

@@ -106,7 +106,7 @@ static void _compress_etc(Image *p_img, float p_lossy_quality, bool force_etc1_f
 		// If VRAM compression is using ETC, but image has alpha, convert to RGBA4444 or LA8
 		// This saves space while maintaining the alpha channel
 		if (detected_channels == Image::USED_CHANNELS_RGBA) {
-			
+
 			if (p_img->has_mipmaps()) {
 				// Image doesn't support mipmaps with RGBA4444 textures
 				p_img->clear_mipmaps();