[Docs] Updated form guidelines with friendly spellcheck

[Jastor11]

Summary

Provide a detailed summary of your PR. Explain how you arrived at your solution. If it includes changes to UI elements include a screenshot or gif.

Changed charaters to characters in the form guidelines.

Checklist

• Check against all themes for compatibility in both light and dark modes
• Checked in mobile
• Checked in Chrome, Safari, Edge, and Firefox
• Props have proper autodocs
• Added documentation
• Checked Code Sandbox works for the any docs examples
• Added or updated jest tests
• Checked for breaking changes and labeled appropriately
• Checked for accessibility including keyboard-only and screenreader modes
• A changelog entry exists and is marked appropriately

[kibanamachine]

Since this is a community submitted pull request, a Jenkins build has not been kicked off automatically. Can an Elastic organization member please verify the contents of this patch and then kick off a build manually?

[cla-checker-service]

💚 CLA has been signed

[cchaos]

Welcome @Jastor11 ! Thanks for your PR.
Would you please sign the CLA linked below. Be sure to use the same email address linked to your Github account.
I'll get our CI (Jenkins, test this) started for you which will run our tests and get a preview built.
You won't need to add a Changelog entry since this only affects the docs site.

[kibanamachine]

Preview documentation changes for this PR: https://eui.elastic.co/pr_3937/

[Jastor11]

Just signed. Let me know if there's anything else you need.

[cchaos]

👍 LGTM, thx!