test: add reference exclusion test for fixed format

Author: gnikit

test/test_server_references.py

@@ -51,3 +51,12 @@ def test_references():
             [free_path, 78, 6, 12],
         ),
     )
+
+
+def test_references_ignore_comments_fixed():
+    string = write_rpc_request(1, "initialize", {"rootPath": str(test_dir / "fixed")})
+    file_path = test_dir / "fixed" / "comment_as_reference.f"
+    string += ref_req(file_path, 3, 22)
+    errcode, results = run_request(string)
+    assert errcode == 0
+    assert len(results[1]) == 2

test/test_source/fixed/comment_as_reference.f

@@ -0,0 +1,5 @@
+      program comment_as_reference
+C     Comment with variable name gets picked as a ref: variable_to_reference
+      real variable_to_reference
+      variable_to_reference = 1
+      end program comment_as_reference