docs: Fix a few typos

[timgates42]

There are small typos in:

• docs/plugins/classic_plugin.rst
• docs/plugins/fixup_plugin.rst
• eyed3/id3/frames.py
• eyed3/mp3/headers.py
• eyed3/utils/init.py
• eyed3/utils/prompt.py

Fixes:

• Should read value rather than valule.
• Should read traditional rather than traditinal.
• Should read referred rather than referrered.
• Should read number rather than nuber.
• Should read input rather than imput.
• Should read individual rather than invidual.
• Should read further rather than futher.
• Should read counter rather than couter.

Semi-automated pull request generated by https://github.com/timgates42/meticulous/blob/master/docs/NOTE.md

[nicfit]

Thanks @timgates42 !