Input action autocompletion leads to doubled quotes

**I'm submitting a...**

- [x] Bug report.
- [ ] Feature request.

## Bug report ##

**What is the current behavior?**
When using `Input.get_action_pressed()` and similar functions, you need to type the name of the action as a string. If you start typing it the auto completion starts suggesting the correct action names, but with quotes. To trigger the autocomplete you still need to start a string either with double or single quotes, the resulting behavior is the same.

**What is the expected behavior?**
The auto completion should either start, without needing quotes to get triggered or the suggested completions should not include quotes.

**Tell us the steps to reproduce the bug, and if possible share a minimal demo of the problem.**
Type the function `Input.is_action_pressed(`. Then you will need to start a string with either the single or the double quotes. Finally start typing the name of an action (eg. (`ui_accept`) and accept the auto completion. this will result in you having either `'"ui_accept"'` or `""ui_accept""` instead of either `'ui_accept'` or `"ui_accept"`.