docs: add missing items for efl_gfx* eo classes

src/lib/efl/interfaces/efl_gfx_color_class.eo

@@ -2,6 +2,7 @@ import efl_gfx_types;
 
 interface Efl.Gfx.Color_Class
 {
+   [[Efl Gfx Color Class interface]]
    methods {
       @property color_class {
          set {
@@ -19,7 +20,7 @@ interface Efl.Gfx.Color_Class
               the given color.
 
               Note: These color values are expected to be premultiplied by \@p a.]]
-            return: bool;
+            return: bool; [[$true if setting the color succeeded, $false otherwise]]
          }
          get {
             [[Get the color of color class.
@@ -32,7 +33,7 @@ interface Efl.Gfx.Color_Class
               to text parts).
 
               Note: These color values are expected to be premultiplied by \@p a.]]
-            return: bool;
+            return: bool; [[$true if getting the color succeeded, $false otherwise]]
          }
          keys {
             color_class: string; [[The name of color class]]

src/lib/efl/interfaces/efl_gfx_size_class.eo

@@ -1,5 +1,6 @@
 interface Efl.Gfx.Size_Class
 {
+   [[Efl Gfx Size Class interface]]
    methods {
       @property size_class {
          set {

src/lib/efl/interfaces/efl_gfx_text_class.eo

@@ -2,6 +2,7 @@ import efl_gfx_types;
 
 interface Efl.Gfx.Text_Class
 {
+   [[Efl Gfx Text Class interface]]
    methods {
       @property text_class {
          set {

src/lib/efl/interfaces/efl_gfx_types.eot

@@ -198,6 +198,7 @@ enum Efl.Image.Load.Error
 }
 
 enum Efl.Gfx.Color_Class.Layer {
+   [[Efl Gfx Color Class layer enum]]
    normal = 0, [[Default color]]
    outline, [[Outline color]]
    shadow [[Shadow color]]