The in-browser Leetcode text editor autocompletes parentheses. (Typing '(' will automatically create a ')' in the text editor.) Unfortunately, Leetcode does not provide settings that disable this feature.
On this page, a Leetcode user has suggested a fix:
Solved it myself. Just copy-paste this into your browser's console: https://pastebin.com/DGW3sBZA. It will stop the auto-completion.
I can't figure out what to do this his code in either Firefox or Chrome.
If possible, how can I use his code to create a permanent solution to the parentheses problem? A permanent solution would persist across tabs, windows, and system restarts. If a permanent solution isn't possible, how can I use his code to create a temporary solution to the parentheses problem? Solutions in either Firefox or Chrome are welcome.