There are a few languages that use only C/C++-style comments but doesn't fully support using shebangs such as Go.

Instead they use the first commented line as the interpreter directive.

Example

Go

//usr/bin/env go run "$0" "$@";exit $?

I'm using JBang which allows scripting in Java using the same syntax.

//usr/bin/env jbang "$0" "$@";exit $?

I tried editing the file but that didn't work.