fix casing in alert-message

Co-authored-by: Arthur Baars <aibaars@github.com>

Author: erik-krogh

ruby/ql/src/queries/security/cwe-912/HttpToFileAccess.ql

@@ -19,4 +19,4 @@ import codeql.ruby.security.HttpToFileAccessQuery
 from Configuration cfg, DataFlow::PathNode source, DataFlow::PathNode sink
 where cfg.hasFlowPath(source, sink)
 select sink.getNode(), source, sink, "Write to file system depends on $@.", source.getNode(),
-  "Untrusted data"
+  "untrusted data"