Do not remove src files for sub-packages

Fixes the condition where sub-packages do not have the src files generated, and links to them fail with a 404.

A current example of this is in the [ponylang/ssl](https://ponylang.github.io/ssl) documentation, where attempting to view any of the source code in [ssl/net](https://ponylang.github.io/ssl/ssl-net--index/) or [ssl/crypto](https://ponylang.github.io/ssl/ssl-crypto--index/) will result in a 404.

The "removing other sources" section of entrypoint.py removed any sources that did not match the library name.

This changes the behaviour to removing sources that do not match library name *or* library_name + '-'. This is consistent with the "removing other docs" section of entrypoint.py.

Author: redvers

entrypoint.py

@@ -61,7 +61,7 @@
 
 print(INFO + "Removing 'other sources'." + ENDC)
 for f in os.listdir(source_dir):
-    if f != library_name:
+    if not (f.startswith(library_name + '-') or (f == library_name)):
         p = os.path.join(source_dir, f)
         if os.path.isfile(p):
             os.remove(p)