docs: fixed small error (#5407)

docs/README.md

@@ -48,7 +48,7 @@ API documentation is written as [TSDoc comments](https://tsdoc.org/) and process
 * Member descriptions should document what a member represents or gets and sets. They should also indicate whether the member is read-only.
 * Event descriptions should begin with "Fired when..." and so should describe when the event fires. Event entries should clearly document any data passed to the handler, with a link to MDN documentation of native Event objects when applicable.
 * Lists need an empty line above to be formatted as HTML list.
-* All documentation is spellchecked with [cSpell](https://cspell.org/) as part of the linting process via a [GitHub Action](https://github.com/marketplace/actions/cspell-action). We recommend using the VS Code extension to catch any misspellings before making your PR. You can run `npx cspell "docs/**/*.html" "docs/**/*.md"` from the CLI to check all files. If there's a false-postitive (a technical term which isn't in the default dictionary) you can add it to the `.spell.json` file's words array in the root.
+* All documentation is spellchecked with [cSpell](https://cspell.org/) as part of the linting process via a [GitHub Action](https://github.com/marketplace/actions/cspell-action). We recommend using the VS Code extension to catch any misspellings before making your PR. You can run `npx cspell "docs/**/*.html" "docs/**/*.md"` from the CLI to check all files. If there's a false-positive (a technical term which isn't in the default dictionary) you can add it to the `.spell.json` file's words array in the root.
 
 ## Writing Examples