add commentary on editionmode height

src/component/Input/TextAreaApp/TextAreaApp.styl

   flex-direction column
   align-items center
   width 100%
-  height calc(100% - 50px)
+  height calc(100% - 50px) // 50px => buttons margin
   &__text
     margin-bottom 25px
     width 100%
-    height calc(100% - 50px)
+    height calc(100% - 50px) // 50px => buttons margin
   &__button
     margin 25px 0
     width 100%
+    text-align right
     &__cancel
       cursor pointer
     &__submit