Reformat code in fs.osfs and add entry to CHANGELOG.md

Author: althonos

CHANGELOG.md

@@ -40,6 +40,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - `WrapCachedDir.isdir` and `WrapCachedDir.isfile` raising a `ResourceNotFound` error on non-existing path ([#470](https://github.com/PyFilesystem/pyfilesystem2/pull/470)).
 - `FTPFS` not listing certain entries with sticky/SUID/SGID permissions set by Linux server ([#473](https://github.com/PyFilesystem/pyfilesystem2/pull/473)).
   Closes [#451](https://github.com/PyFilesystem/pyfilesystem2/issues/451).
+- `scandir` iterator not being closed explicitly in `OSFS.scandir`, occasionally causing a `ResourceWarning` 
+  to be thrown. Closes [#311](https://github.com/PyFilesystem/pyfilesystem2/issues/311).
 
 
 ## [2.4.12] - 2021-01-14

fs/osfs.py

@@ -496,15 +496,19 @@ def _scandir(self, path, namespaces=None):
                         if requires_stat:
                             stat_result = dir_entry.stat()
                             if "details" in namespaces:
-                                info["details"] = self._make_details_from_stat(stat_result)
+                                info["details"] = self._make_details_from_stat(
+                                    stat_result
+                                )
                             if "stat" in namespaces:
                                 info["stat"] = {
                                     k: getattr(stat_result, k)
                                     for k in dir(stat_result)
                                     if k.startswith("st_")
                                 }
                             if "access" in namespaces:
-                                info["access"] = self._make_access_from_stat(stat_result)
+                                info["access"] = self._make_access_from_stat(
+                                    stat_result
+                                )
                         if "lstat" in namespaces:
                             lstat_result = dir_entry.stat(follow_symlinks=False)
                             info["lstat"] = {