remove references to 'Cursor.clipIdx' and delete that function once it is no longer used

fcore/cursor.sml

@@ -1251,38 +1251,4 @@ struct
           end
       | [] => true
     end
-
-  (* Prerequisite: lineGap is moved to cursorIdx *)
-  fun clipIdx (lineGap: LineGap.t, cursorIdx) =
-    let
-      val {rightStrings, idx = bufferIdx, ...} = lineGap
-    in
-      (* We are trying to check if cursorIdx is within the buffer. *)
-      case rightStrings of
-        _ :: _ :: _ =>
-          (* if there is a string after the hd, 
-           * we are definitely in a valid idx and should return it *)
-          cursorIdx
-      | [hd] =>
-          let
-            val strIdx = cursorIdx - bufferIdx
-          in
-            if strIdx < String.size hd - 1 then
-              (* if we are before the last char in the string.
-               * Unix file endings always have \n at the end
-               * but we do not want cursor to ever go to end
-               * as vi also does not go to the very end.
-               * This is why we check strIdx is before the last char. 
-               * *)
-              cursorIdx
-            else
-              (* if end of buffer - 2 is greater than 0, then that;
-               * else, 0 *)
-              Int.max (bufferIdx + String.size hd - 2, 0)
-          end
-      | [] =>
-          (* if end of buffer - 2 is greater than 0, then that;
-           * else, 0 *)
-          Int.max (bufferIdx - 2, 0)
-    end
 end

fcore/normal-mode/make-normal-delete.sml

@@ -164,7 +164,11 @@ struct
       let
         val low = Int.min (cursorIdx, otherIdx)
         val high = Int.max (cursorIdx, otherIdx)
-        val high = Cursor.clipIdx (buffer, high)
+        val high =
+          if high >= #textLength buffer - 2 then
+            Int.max (#textLength buffer - 2, 0)
+          else
+            high
         val length = high - low
 
         val buffer = LineGap.goToIdx (high, buffer)
@@ -183,7 +187,11 @@ struct
         * is no longer a valid idx,
         * clip cursorIdx to the end. *)
         val buffer = LineGap.goToIdx (low, buffer)
-        val cursorIdx = Cursor.clipIdx (buffer, low)
+        val cursorIdx =
+          if low >= #textLength buffer then
+            Int.max (#textLength buffer - 2, low)
+          else
+            low
       in
         NormalFinish.buildTextAndClear
           (app, buffer, cursorIdx, searchList, initialMsg, time)