Bug in module definition via the keyword

There are two ways of creating a module.
1. File with .ql extension
2. via `module` keyword

If the module was defined via keyword then it may wrongly assume there
is a file named <module>.ql while concating all modules into the
monolith. This isn't ideal.

This is a low prio.

Author: weirdsmiley

src/parser.rs

@@ -781,7 +781,8 @@ impl Parser {
                 Err(QccErrorKind::ParseError)?
             }
 
-            // TODO:
+            // TODO: This may not exist if the module was defined via the
+            // `module` keyword and not in a separate file.
             let import_file = delimited_dir_name.clone() + &import_module + ".ql";
             let import_session = Parser::new(vec![import_file.as_str()])?;
             match import_session {