[DOCS] Add title and extension to LICENSE file

[waldyrious]

The title is not legally mandated, but it's convenient for human consumption; it also works as additional metadata, and is part of the recommended license template text (see http://choosealicense.com/licenses/isc/ and https://opensource.org/licenses/isc-license).

The extension is needed to trigger soft text-wrapping on the GitHub interface, which otherwise displays long lines overflowing the container.

This PR is part of a project to improve the consistency and visibility of the ISC license. See https://github.com/github/choosealicense.com/issues/377 for more details.

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/cc @Abdizriel

• [x] I have read the Contributing Documents
• [x] My commit(s) follow the commit message guidelines
• [ ] Project tests pass (npm test)
• [ ] Project tests coverage is at least 90%