Remove contintuation prompt

We are not able to easily replicate it after the introduction of a new
highlight for the submitted user input, so we might as well remove it
altogether.

Author: iamFIREcracker

aider/io.py

@@ -648,9 +648,6 @@ def _(event):
                         if self.clipboard_watcher:
                             self.clipboard_watcher.start()
 
-                    def get_continuation(width, line_number, is_soft_wrap):
-                        return self.prompt_prefix
-
                     line = self.prompt_session.prompt(
                         show,
                         default=default,
@@ -660,7 +657,6 @@ def get_continuation(width, line_number, is_soft_wrap):
                         style=style,
                         key_bindings=kb,
                         complete_while_typing=True,
-                        prompt_continuation=get_continuation,
                     )
                     self.display_user_input(show + line)
                 else: