Cleanup: move model authors from the doc-string to the implementation

There is no need for details like this in API doc-strings.

source/blender/editors/gpencil/gpencil_add_monkey.c

@@ -823,6 +823,8 @@ static const ColorTemplate gp_monkey_pct_pupils = {
 
 void ED_gpencil_create_monkey(bContext *C, Object *ob, float mat[4][4])
 {
+  /* Original model created by Matias Mendiola. */
+
   Main *bmain = CTX_data_main(C);
   Scene *scene = CTX_data_scene(C);
   bGPdata *gpd = (bGPdata *)ob->data;

source/blender/editors/gpencil/gpencil_add_stroke.c

@@ -192,6 +192,8 @@ static const ColorTemplate gp_stroke_material_grey = {
 
 void ED_gpencil_create_stroke(bContext *C, Object *ob, float mat[4][4])
 {
+  /* Original design created by Daniel M. Lara and Matias Mendiola. */
+
   Main *bmain = CTX_data_main(C);
   Scene *scene = CTX_data_scene(C);
   bGPdata *gpd = (bGPdata *)ob->data;

source/blender/editors/include/ED_gpencil.h

@@ -403,12 +403,11 @@ void ED_gpencil_stroke_init_data(struct bGPDstroke *gps,
  */
 void ED_gpencil_create_blank(struct bContext *C, struct Object *ob, float mat[4][4]);
 /**
- * Add a 2D Suzanne (original model created by Matias Mendiola).
+ * Add a 2D Suzanne.
  */
 void ED_gpencil_create_monkey(struct bContext *C, struct Object *ob, float mat[4][4]);
 /**
- * Add a Simple stroke with colors
- * (original design created by Daniel M. Lara and Matias Mendiola).
+ * Add a Simple stroke with colors.
  */
 void ED_gpencil_create_stroke(struct bContext *C, struct Object *ob, float mat[4][4]);
 /**