simplify folder name

test/data/text_reference.md

@@ -0,0 +1,21 @@
+[reference link][1]
+
+[1]: http://example.com
+
+[one][website] with a semantic name
+
+[website]: http://example.com
+
+[one][404] with no definition
+
+[multiline
+one][website] defined on 2 lines
+
+[one][Label] with a mixed case label and an upper case definition
+
+[LABEL]: http://example.com
+
+[one]
+[1] with the a label on the next line
+
+[`link`][website]