Update copyright notice of docs index page

[caleb531]

@eliotwrobson Just something I noticed and wanted to correct. I didn't change anything else, since it makes sense to me to remove the irrelevant README badges for the documentation site. Same for the links to the other documentation pages, as the links would probably break / navigate to the incorrect files anyway (we want to keep the user in the documentation site, after all).

One other thing: does automata-lib[visual] really require quotes to install?

pip install 'automata-lib[visual]'

...versus just:

pip install automata-lib[visual]

[coveralls]

coverage: 99.64%. remained the same
when pulling c58b594 on sync-docs-index-page-with-readme
into 20d8233 on develop.

[eliotwrobson]

One small change.

Regarding the quotes in the install instructions, I believe those are actually required (I get an error when I don't use them).