Improve ModalCursorShapeConfig for various input modes (#1900)

- Also display a beam cursor for Vi "insert multiple" mode (visual block insert).
- Also display an underline cursor for Vi "replace single" mode.
- Display a beam in Emacs mode (like Vi's insert).

Author: Freed-Wu

Diff for: src/prompt_toolkit/cursor_shapes.py

@@ -69,10 +69,23 @@ class ModalCursorShapeConfig(CursorShapeConfig):
 
     def get_cursor_shape(self, application: Application[Any]) -> CursorShape:
         if application.editing_mode == EditingMode.VI:
-            if application.vi_state.input_mode == InputMode.INSERT:
+            if application.vi_state.input_mode in {
+                InputMode.NAVIGATION,
+            }:
+                return CursorShape.BLOCK
+            if application.vi_state.input_mode in {
+                InputMode.INSERT,
+                InputMode.INSERT_MULTIPLE,
+            }:
                 return CursorShape.BEAM
-            if application.vi_state.input_mode == InputMode.REPLACE:
+            if application.vi_state.input_mode == {
+                InputMode.REPLACE,
+                InputMode.REPLACE_SINGLE,
+            }:
                 return CursorShape.UNDERLINE
+        elif application.editing_mode == EditingMode.EMACS:
+            # like vi's INSERT
+            return CursorShape.BEAM
 
         # Default
         return CursorShape.BLOCK