docs: Clarify how Gesture objects are used

Ref T8502

src/lib/evas/gesture/efl_canvas_gesture_double_tap.eo

@@ -3,6 +3,8 @@ class @beta Efl.Canvas.Gesture_Double_Tap extends Efl.Canvas.Gesture
    [[Double-tap gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,double_tap] for a description of the Double-tap gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    data: null;
    c_prefix: efl_gesture_double_tap;

src/lib/evas/gesture/efl_canvas_gesture_flick.eo

@@ -5,6 +5,8 @@ class @beta Efl.Canvas.Gesture_Flick extends Efl.Canvas.Gesture
    [[Flick gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,flick] for a description of the Flick gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    c_prefix: efl_gesture_flick;
    methods {

src/lib/evas/gesture/efl_canvas_gesture_long_tap.eo

@@ -3,6 +3,8 @@ class @beta Efl.Canvas.Gesture_Long_Tap extends Efl.Canvas.Gesture
    [[Long-tap gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,long_tap] for a description of the Long-tap gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    data: null;
    c_prefix: efl_gesture_long_tap;

src/lib/evas/gesture/efl_canvas_gesture_momentum.eo

@@ -5,6 +5,8 @@ class @beta Efl.Canvas.Gesture_Momentum extends Efl.Canvas.Gesture
    [[Momentum gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,momentum] for a description of the Momentum gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    c_prefix: efl_gesture_momentum;
    methods {

src/lib/evas/gesture/efl_canvas_gesture_tap.eo

@@ -3,6 +3,8 @@ class @beta Efl.Canvas.Gesture_Tap extends Efl.Canvas.Gesture
    [[Tap gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,tap] for a description of the Tap gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    data: null;
    c_prefix: efl_gesture_tap;

src/lib/evas/gesture/efl_canvas_gesture_triple_tap.eo

@@ -3,6 +3,8 @@ class @beta Efl.Canvas.Gesture_Triple_Tap extends Efl.Canvas.Gesture
    [[Triple-tap gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,triple_tap] for a description of the Triple-tap gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    data: null;
    c_prefix: efl_gesture_triple_tap;

src/lib/evas/gesture/efl_canvas_gesture_zoom.eo

@@ -3,6 +3,8 @@ class @beta Efl.Canvas.Gesture_Zoom extends Efl.Canvas.Gesture
    [[Zoom gesture class holding state information.
      See @Efl.Canvas.Gesture to see what this state is and
      @[Efl.Gesture.Events.gesture,zoom] for a description of the Zoom gesture.
+
+     Application developers receive these objects inside a gesture event and do not typically need to create their own.
    ]]
    c_prefix: efl_gesture_zoom;
    methods {

src/lib/evas/gesture/efl_gesture_events.eo

@@ -1,5 +1,7 @@
 interface @beta Efl.Gesture.Events
 {
+   [[Interface for objects capable of emitting gesture events, like @Efl.Canvas.Object.
+   ]]
    event_c_prefix: efl;
    events {
       gesture,tap: Efl.Canvas.Gesture_Tap; [[Emitted when a Tap gesture has been detected.