Search for similar/duplicates with New Issue title

[jtagcat]

Feature Description

• A way to force duplicate search, or two-in-one for speeding it up
• Searches also closed issues, mitigates the 'I already searched for dupes' (from open issues) problem

Updating/querying doesn't have to be real-time, imo it would be better, if it doesn't disrupt the user while typing (and giving more text for fuzzy search).

Screenshots