Cleaner reader API

- added types annotations in docstring as cython doesn't forward it to gen code
- added a dummy __enter__ and __exit__ so user can use it as a contextmanager for clarity

Author: renaud gaudin

libzim/reader.py

@@ -1,4 +1,16 @@
-# flake8: noqa
+""" libzim reader module
+
+    - File to open and read ZIM files
+    - Article are returned by File on get_article() and get_article_by_id()
+    - NotFound is raised on incorrect article URL query
+
+    Usage:
 
+    with File(pathlib.Path("myfile.zim")) as zf:
+        article = zf.get_article(zf.main_page_url)
+        print(f"Article {article.title} at {article.url} is {article.content.nbytes}b")
+    """
+
+# flake8: noqa
 from .wrapper import FilePy as File, NotFound
 from .wrapper import ReadArticle as Article