🔧 explicitly import to force populate nlpurify/legacy

- fixes #8 as rtd fails to call the internal submodule
- init time option registration for legacy is not provided
- legacy is kept only to support old code styles

docs/conf.py

@@ -14,6 +14,7 @@
 # ? also import the module itself, to populate static contents like version
 sys.path.append(os.path.abspath(".."))
 import nlpurify
+import nlpurify.legacy # explictly import gh#8
 
 project = 'NLPurify'
 copyright = '2024, shark-utilities developers'