Project language bar: SQL not detected

Summary

The only language detected in https://octo.sh/Gateway/Gateway/ is 100% Common Lisp, even though I have a substantial body of SQL code in there at https://octo.sh/Gateway/Gateway/tree/master/src/sql/src/install and https://octo.sh/Gateway/Gateway/tree/master/src/sql/src/yesql.

Steps to reproduce

Visit https://octo.sh/Gateway/Gateway/ and mouseover on the language bar.

Example Project

Code percentages are not shown on my projects on GitLab.com, therefore I cannot reproduce it here.

GitLab Enterprise Edition 11.9.1-ee

What is the current bug behavior?

SQL is not detected as a language.

What is the expected correct behavior?

SQL is detected as a language.

Relevant logs and/or screenshots

Output of checks

None

Results of GitLab environment info

None

Results of GitLab application Check

None

Possible fixes

Don't know yet.