fix: add test with rougailcli that assign a symlinkoption

tests/rougailcli_file/symlink_rougailcli.txt

@@ -0,0 +1 @@
+["unable to load \"Main namespace name\", is a symlink option so we cannot set the value \"doc\", it will be ignored when loading from the YAML file \"symlink_rougailcli.yml\""]

tests/rougailcli_file/symlink_rougailcli.yml

@@ -0,0 +1,4 @@
+---
+main_structural_directories:
+  - structures
+s: doc

tests/test_load.py

@@ -289,3 +289,21 @@ def test_cli_rougailcli_choice():
             data = loads(fh.read())
         assert ret == (True, data), str(filename.absolute())
     os.environ = save
+
+
+def test_cli_rougailcli_symlink():
+    save = os.environ.copy()
+    with chdir(test_dir / 'rougailcli_file'):
+        os.environ["ROUGAILCLI_CLI.CONFIG_FILE"] = 'symlink_rougailcli.yml'
+        with warnings.catch_warnings(record=True) as rougail_wn:
+            warnings.simplefilter("always", UserWarning)
+            main(["-o", "doc", "--doc.output_format", "asciidoc"], do_not_print=True)
+        ret = [str(w.message) for w in rougail_wn]
+        filename = Path('symlink_rougailcli.txt')
+        if not filename.is_file():
+            with filename.open('w') as fh:
+                fh.write(dumps([str(w.message) for w in rougail_wn]))
+        with filename.open() as fh:
+            data = loads(fh.read())
+        assert ret == data, str(filename.absolute())
+    os.environ = save