Code quality: Fix header guards consistency

Adds `header_guards.sh` bash script, used in CI to validate future
changes. Can be run locally to fix invalid header guards.

servers/rendering/renderer_rd/effects/bokeh_dof.h

@@ -117,4 +117,4 @@ public:
 
 } // namespace RendererRD
 
-#endif // !BOKEH_DOF_RD_H
+#endif // BOKEH_DOF_RD_H

servers/rendering/renderer_rd/effects/copy_effects.h

@@ -28,8 +28,8 @@
 /* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
 /*************************************************************************/
 
-#ifndef COPY_RD_H
-#define COPY_RD_H
+#ifndef COPY_EFFECTS_RD_H
+#define COPY_EFFECTS_RD_H
 
 #include "servers/rendering/renderer_rd/pipeline_cache_rd.h"
 #include "servers/rendering/renderer_rd/shaders/effects/blur_raster.glsl.gen.h"
@@ -343,4 +343,4 @@ public:
 
 } // namespace RendererRD
 
-#endif // !COPY_RD_H
+#endif // COPY_EFFECTS_RD_H

servers/rendering/renderer_rd/effects/resolve.h

@@ -71,4 +71,4 @@ public:
 
 } // namespace RendererRD
 
-#endif // !RESOLVE_RD_H
+#endif // RESOLVE_RD_H

servers/rendering/renderer_rd/effects/ss_effects.h

@@ -505,4 +505,4 @@ private:
 
 } // namespace RendererRD
 
-#endif // !SS_EFFECTS_RD_H
+#endif // SS_EFFECTS_RD_H

servers/rendering/renderer_rd/effects/tone_mapper.h

@@ -149,4 +149,4 @@ public:
 
 } // namespace RendererRD
 
-#endif // !TONE_MAPPER_RD_H
+#endif // TONE_MAPPER_RD_H

servers/rendering/renderer_rd/effects/vrs.h

@@ -72,4 +72,4 @@ public:
 
 } // namespace RendererRD
 
-#endif // !VRS_RD_H
+#endif // VRS_RD_H