Cleanup: use C comments for descriptive text

Follow our code style guide by using C-comments for text descriptions.

source/blender/python/intern/bpy.c

@@ -147,7 +147,7 @@ static PyObject *bpy_blend_paths(PyObject *UNUSED(self), PyObject *args, PyObjec
   return list;
 }
 
-// PyDoc_STRVAR(bpy_user_resource_doc[] = // now in bpy/utils.py
+// PyDoc_STRVAR(bpy_user_resource_doc[] = /* now in bpy/utils.py */
 static PyObject *bpy_user_resource(PyObject *UNUSED(self), PyObject *args, PyObject *kw)
 {
   const struct PyC_StringEnumItems type_items[] = {

source/blender/python/intern/bpy_app_ffmpeg.c

@@ -75,7 +75,7 @@ static PyObject *make_ffmpeg_info(void)
     return NULL;
   }
 
-#if 0  // UNUSED
+#if 0 /* UNUSED */
 #  define SetIntItem(flag) PyStructSequence_SET_ITEM(ffmpeg_info, pos++, PyLong_FromLong(flag))
 #endif
 #ifndef WITH_FFMPEG

source/blender/python/intern/bpy_app_sdl.c

@@ -89,7 +89,7 @@ static PyObject *make_sdl_info(void)
     SDL_GetVersion(&version);
     sdl_available = true;
   }
-#  else  // WITH_SDL_DYNLOAD=OFF
+#  else /* WITH_SDL_DYNLOAD=OFF */
   sdl_available = true;
 #    if SDL_MAJOR_VERSION >= 2
   SDL_GetVersion(&version);
@@ -107,7 +107,7 @@ static PyObject *make_sdl_info(void)
   }
   SetObjItem(PyBool_FromLong(sdl_available));
 
-#else  // WITH_SDL=OFF
+#else /* WITH_SDL=OFF */
   SetObjItem(PyBool_FromLong(0));
   SetObjItem(PyC_Tuple_Pack_I32(0, 0, 0));
   SetStrItem("Unknown");

source/blender/python/intern/bpy_driver.c

@@ -266,7 +266,7 @@ static void pydriver_error(ChannelDriver *driver)
           "\nError in Driver: The following Python expression failed:\n\t'%s'\n\n",
           driver->expression);
 
-  // BPy_errors_to_report(NULL); // TODO - reports
+  // BPy_errors_to_report(NULL); /* TODO - reports */
   PyErr_Print();
   PyErr_Clear();
 }
@@ -613,7 +613,7 @@ float BPY_driver_exec(struct PathResolvedRNA *anim_rna,
 
       fprintf(
           stderr, "\tBPY_driver_eval() - couldn't add variable '%s' to namespace\n", dvar->name);
-      // BPy_errors_to_report(NULL); // TODO - reports
+      // BPy_errors_to_report(NULL); /* TODO - reports */
       PyErr_Print();
       PyErr_Clear();
     }

source/blender/python/intern/bpy_interface.c

@@ -91,7 +91,7 @@ static int py_call_level = 0;
 /* Set by command line arguments before Python starts. */
 static bool py_use_system_env = false;
 
-// #define TIME_PY_RUN // simple python tests. prints on exit.
+// #define TIME_PY_RUN /* simple python tests. prints on exit. */
 
 #ifdef TIME_PY_RUN
 #  include "PIL_time.h"

source/blender/python/intern/bpy_rna.c

@@ -722,7 +722,7 @@ PyObject *pyrna_math_object_from_array(PointerRNA *ptr, PropertyRNA *prop)
           }
           else {
             /* Order will be updated from callback on use. */
-            // TODO, get order from RNA
+            /* TODO, get order from RNA. */
             PyObject *eul_cb = Euler_CreatePyObject_cb(
                 ret, EULER_ORDER_XYZ, mathutils_rna_array_cb_index, MATHUTILS_CB_SUBTYPE_EUL);
             Py_DECREF(ret); /* The euler owns 'ret' now. */
@@ -6048,7 +6048,7 @@ static PyObject *pyrna_func_call(BPy_FunctionRNA *self, PyObject *args, PyObject
 
   /* enable this so all strings are copied and freed after calling.
    * this exposes bugs where the pointer to the string is held and re-used */
-  // #define DEBUG_STRING_FREE
+  /* #define DEBUG_STRING_FREE */
 
 #ifdef DEBUG_STRING_FREE
   PyObject *string_free_ls = PyList_New(0);
@@ -8820,7 +8820,10 @@ static PyObject *pyrna_register_class(PyObject *UNUSED(self), PyObject *py_class
   /* Old srna still references us, keep the check in case registering somehow can free it. */
   if (RNA_struct_py_type_get(srna)) {
     RNA_struct_py_type_set(srna, NULL);
-    // Py_DECREF(py_class); /* Should be able to do this XXX since the old RNA adds a new ref. */
+#if 0
+    /* Should be able to do this XXX since the old RNA adds a new ref. */
+    Py_DECREF(py_class);
+#endif
   }
 
   /* Can't use this because it returns a dict proxy