Autocomplete inserts duplicate protocol

When editing a URL in the request URL input, accepting the http:// autocomplete suggestion can insert the protocol before an existing ://, resulting in an invalid duplicated URL.

Steps to reproduce

1. Enter a URL like: https://rickandmortyapi.com/api/character
2. Place the cursor right after http / https, but before ://.
3. Delete the s from https, so the text becomes: http://rickandmortyapi.com/api/character
4. Accept the http:// autocomplete suggestion with Enter.

Actual behavior

The URL becomes: http://://rickandmortyapi.com/api/character The autocomplete seems to insert http:// at the cursor position without accounting for the existing :// immediately after the cursor.

Expected behavior

Accepting the autocomplete suggestion should keep the URL as: http://rickandmortyapi.com/api/character or replace the existing protocol section cleanly without duplicating ://.