LibLine: Handle Ctrl-C and Ctrl-D in a way similar to other line editors

Makes C-c print "^C" and continue prompting on a new line.
Also fixes a problem where an interrupted get_line() would need more
read()'s than required to update the display.

Libraries/LibLine/InternalFunctions.cpp

@@ -168,6 +168,7 @@ void Editor::finish_edit()
     if (!m_always_refresh) {
         m_input_error = Error::Eof;
         finish();
+        really_quit_event_loop();
     }
 }