docs: ector: document ector cairo surface classes

For both the cairo and the cairo software surfaces.

src/lib/ector/cairo/ector_cairo_software_surface.eo

@@ -1,5 +1,9 @@
 class Ector.Cairo_Software.Surface (Ector.Cairo.Surface, Ector.Software.Buffer.Base)
 {
+   [[Ector surface on a cairo software backend
+
+   Used to render ector content into a cairo software backend.
+   ]]
    eo_prefix: ector_cairo_software_surface;
    legacy_prefix: null;
    methods {}

src/lib/ector/cairo/ector_cairo_surface.eo

@@ -2,16 +2,21 @@ type @extern cairo_t: void *;
 
 class Ector.Cairo.Surface (Eo.Base, Ector.Generic.Surface)
 {
+   [[Ector surface on a cairo backend
+
+   Used to render ector content into a cairo backend.
+   ]]
    eo_prefix: ector_cairo_surface;
    legacy_prefix: null;
    methods {
       @property context {
+         [[Cairo context]]
          set {
 	 }
 	 get {
 	 }
 	 values {
-	    ctx: cairo_t *;
+	    ctx: cairo_t *; [[Cairo context]]
 	 }
       }
       symbol_get {

src/lib/eldbus/eldbus_model_connection.eo

@@ -28,7 +28,7 @@ class Eldbus.Model_Connection (Eo.Base, Efl.Model.Base) {
     @property private {
             [[Indicate if the DBus connection is shared or private]]
             values {
-                private: bool; [[Private DBus connection]]
+                private_: bool; [[Private DBus connection]]
             }
         }
     }

src/lib/eldbus/eldbus_model_object.eo

@@ -43,7 +43,7 @@ class Eldbus.Model_Object (Eo.Base, Efl.Model.Base) {
     @property private {
             [[Indicate if the DBus connection is shared or private]]
             values {
-                private: bool; [[Private DBus connection]]
+                private_: bool; [[Private DBus connection]]
             }
         }
     @property bus {