Rust: remove useless blank line

Co-authored-by: Simon Friis Vindum <simonfv@gmail.com>

rust/codegen/codegen.sh

@@ -4,7 +4,6 @@ set -eu
 
 source misc/bazel/runfiles.sh 2>/dev/null || source external/ql+/misc/bazel/runfiles.sh
 
-
 ast_generator="$(rlocation "$1")"
 ast_generator_manifest="$(rlocation "$2")"
 codegen="$(rlocation "$3")"