Add extension_summary.py.

extension_summary.py

@@ -0,0 +1,17 @@
+import collections
+
+from voussoirkit import spinal
+
+counts = collections.Counter()
+extensions = {}
+walker = spinal.walk_generator()
+for file in walker:
+    extensions.setdefault(file.extension, []).append(file)
+    counts[file.extension] += 1
+
+for (extension, count) in counts.most_common():
+    files = extensions[extension]
+    print(f'{extension.with_dot}: {len(files)}')
+    if len(files) < 5:
+        for file in files:
+            print(f'    {file.absolute_path}')