Move pronunciations.py to extractor/en/pronunciations.py

This file is only used in en edition extractor, move it to the
`extractor/en` folder is for preparing move `zh_pron_tags.json` file
to Python code.

src/wiktextract/extractor/en/page.py

@@ -770,7 +770,7 @@ def parse_language(
     defined on the page one at a time.  (Individual word senses for the
     same part-of-speech are typically encoded in the same entry.)"""
     # imported here to avoid circular import
-    from wiktextract.pronunciations import parse_pronunciation
+    from .pronunciations import parse_pronunciation
 
     assert isinstance(wxr, WiktextractContext)
     assert isinstance(langnode, WikiNode)