added keyboard shortcuts to docs

[mishabruml]

added keyboard shortcuts to docs, close #1904

[CLAassistant]

All committers have signed the CLA.

[jennifer-shehane]

Thanks for adding this! Made a few edits, but good to merge after that.

[CLAassistant]

Thank you for your submission, we really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
1 out of 2 committers have signed the CLA.

✅ kevinold
❌ Misha Bruml

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[mishabruml]

Thanks for adding this! Made a few edits, but good to merge after that.

No worries, happy to help, the only problem is I'm having issues with the CLA, I've hit the cloudflare error page so perhaps the service is down?

[jennifer-shehane]

Yup, cla-assistant is down. Opened an issue cla-assistant/cla-assistant#493

[mishabruml]

@jennifer-shehane see comment here cla-assistant/cla-assistant#493 (comment)