Searching in github for language:Bicep returns zero resuilts

1) Go to github: https://github.com/
2) Search for resourceGroup (all github)
- 860K results
3) Click Advanced Search (bottom)
4) Set language to Bicep
5) Search
!) No results

- This returns a bunch of results:
https://github.com/Azure/bicep/search?q=resourceGroup
- As does the same query with "extension:bicep"
https://github.com/search?q=resourceGroup+extension%3Abicep&type=Code&ref=advsearch&l=&l=
!) But "language:Bicep" returns nothing:
https://github.com/search?q=resourceGroup+language%3ABicep&type=Code&ref=advsearch&l=&l=

Start by reproducing the linked GitHub searches for resourceGroup with language:Bicep, extension:bicep, and the Azure/bicep repository search. Trace how GitHub's language filter handles Bicep and verify that the language-specific query returns the same relevant results as the extension query; done means language:Bicep no longer returns zero results.

Written by the indexing model from the issue text.