[BUG] Numerals in prefix break Custom Search

[trappleton]

Deployment details:

• Flame version 2.3.1

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Bug description:

Including a numeral as part of a Custom Search prefix breaks that search. Instead, it performs a search on the primary or secondary search engine.

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Steps to reproduce:

Here's how I did it, at least:

1. Add a new Custom Search provider. In my case, it was the Baldur's Gate 3 wiki.
2. For the Query Template, I used this: https://bg3.wiki/w/index.php?title=Special%3ASearch&go=Go&search=
3. For the Prefix, type "bg3" without quotes.
4. Save and go back to the Flame homepage. Enter "/bg3 cleric" without quotes and hit enter. You'll be taken to a different search provider.

Cheers!