[fixed] stale link in react-modal/docs/styles/classes.md

[hamirmahal]

All this does is change the "default content styles" hyperlink to index.md instead of README.md, since I think the link to README.md is stale since at least Dec 9, 2019 with commit e5fe406.

Fixes #833.

Changes proposed:

• Update "default content styles" hyperlink in classes.md to link to index.md instead of README.md

Upgrade Path (for changed or removed APIs):
I don't think this is applicable for this pull request.

Acceptance Checklist:

• The commit message follows the guidelines in CONTRIBUTING.md.
• Documentation (README.md) and examples have been updated as needed.
• If this is a code change, a spec testing the functionality has been added.
• If the commit message has [changed] or [removed], there is an upgrade path above.

[coveralls]

Coverage remained the same at 82.632% when pulling cd3e585 on hamirmahal:patch-2 into b2e58e7 on reactjs:master.

[diasbruno]

Thanks, @hamirmahal!! 👍

[hamirmahal]

You're welcome! Happy I was able to help.

…

On Mon, 2 Nov 2020 at 12:14, Bruno Dias ***@***.***> wrote: Thanks, @hamirmahal <https://github.com/hamirmahal>!! 👍 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#834 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AKLKAFAHZF6WXIBQ6OOVWLTSN4HJ3ANCNFSM4S33FLBQ> .