Cleanup: consistent TODO/FIXME formatting for names

Following the most widely used convention for including todo's in
the code, that is: `TODO(name):`, `FIXME(name)` ... etc.

source/blender/gpu/opengl/gl_shader.cc

@@ -219,7 +219,7 @@ void GLShader::unbind(void)
 /* -------------------------------------------------------------------- */
 /** \name Transform feedback
  *
- * TODO(fclem) Should be replaced by compute shaders.
+ * TODO(fclem): Should be replaced by compute shaders.
  * \{ */
 
 /* Should be called before linking. */