[ranas-mukminov]

Fixes #160

Problem: the www, protocol and email rules returned True in silent (validation) mode without advancing state.pos, so parseLinkLabel looped forever on a link whose text starts a www autolink after other text (e.g. see www.example.com).

Change:

• mdit_py_plugins/gfm_autolink/index.py: all three rules now advance state.pos by one in silent mode, without touching pending. One char (not the full match) so the label scan still sees every character, including a closing bracket a greedy match would overshoot.

Tests:

• Issue repro: both hanging inputs now render (see www.example.com as a link, link www.example.com as a link with emphasis); all previously working cases render unchanged.
• Existing tests/test_gfm_autolink.py fixture suite: 20 passed.
• python3 -m py_compile on the patched file: OK