Update PositionTypeEnum descriptions

app/graphql/types/notes/position_type_enum.rb

@@ -6,8 +6,8 @@ module Types
       graphql_name 'DiffPositionType'
       description 'Type of file the position refers to'
 
-      value 'text'
-      value 'image'
+      value 'text', description: "A text file"
+      value 'image', description: "An image"
     end
   end
 end

doc/api/graphql/reference/index.md

@@ -5386,8 +5386,8 @@ Type of file the position refers to.
 
 | Value | Description |
 | ----- | ----------- |
-| `image` |  |
-| `text` |  |
+| `image` | An image |
+| `text` | A text file |
 
 ### `EntryType`