Add comments on MouseReportMode

lib/src/core/mouse/mode.dart

@@ -13,11 +13,19 @@ enum MouseMode {
 
 /// https://terminalguide.namepad.de/mouse/
 enum MouseReportMode {
+  /// The default mouse reporting mode where digits are encoded as bytes with
+  /// `32 + code`. This mode has a range from 1 to 223.
   normal,
 
+  /// When code < 96 this is the same as [normal], otherwise the `code + 32` is
+  /// encoded as 2 bytes in UTF-8. This mode has a range from 1 to 2015.
   utf,
 
+  /// In this mode the code are encoded as 10-based numbers. Tha range is
+  /// unlimited.
   sgr,
 
+  /// Similar to [sgr], the difference is that the button id is encoded as
+  /// `32 + code`.
   urxvt,
 }