Fix comment: clarify root-level files have no subject entity

Author: neuromechanist

tools/schemacode/src/bidsschematools/tests/test_render_text.py

@@ -118,7 +118,7 @@ def test_make_filename_template(schema_obj, schema_dir, placeholders):
             continue
         if line.startswith("    [ses-<label>/]"):
             continue
-        # Some files (e.g., EMG coordsystem) can have optional subject for root-level placement
+        # Skip patterns with optional subject (e.g., root-level EMG coordsystem has no subject)
         if line.lstrip().startswith("[sub-<label>]"):
             continue
 
@@ -157,7 +157,7 @@ def test_make_filename_template(schema_obj, schema_dir, placeholders):
             continue
         if line.startswith("    [ses-<label>/]"):
             continue
-        # Some files (e.g., EMG coordsystem) can have optional subject for root-level placement
+        # Skip patterns with optional subject (e.g., root-level EMG coordsystem has no subject)
         if line.lstrip().startswith("[sub-<label>]"):
             continue