Remove useless shebangs (#141)

Fixes #140

Changes proposed in this pull request:

* Remove shebangs from `time.py` and `number.py`

src/humanize/number.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 """Humanizing functions for numbers."""
 from __future__ import annotations
 

src/humanize/time.py

@@ -1,5 +1,3 @@
-#!/usr/bin/env python
-
 """Time humanizing functions.
 
 These are largely borrowed from Django's `contrib.humanize`.