Update README.md

[zimmah]

Clarify alternative build-in functions

[SleeplessByte]

I will point you to the appropriate places. Feel free to ping me on slack if needed.

• The file that causes the difference is .meta/hints.md
• It allow us to generate a different README.md
• How it's generated is explained in CONTRIBUTING.md#improving-the-readmemd

In order to PR this for JavaScript:

• Edit .meta/hints.md
• Run bin/fetch_configlet or bin/fetch_configlet.ps1 to get configlet (or configlet.exe)
• Run bin/configlet generate -o square-root . to regenerate the README.md

Your PR will have 2 changed files:

• .meta/hints.md
• README.md

I will also post this on your PR.

[zimmah]

Thanks, I pinged you on slack