Two small typos in matcher docs

[danielrentz]

Describe the bug
The page for matchers contains two typos:

This allows to logically combine mutliple matchers. The result is a new matchers that requires both (and) or one of the matchers (or) to return true.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://sinonjs.org/releases/v9.2.1/matchers/
2. Scroll down to 'Custom matchers'
3. See error

Expected behavior
mutliple => multiple
matchers => matcher

[mantoni]

Thank you. Would you care to make these changes yourself?

You can find instructions on how to make documentation changes here: https://github.com/sinonjs/sinon/blob/master/docs/CONTRIBUTING.md

[danielrentz]

Sure. Where should I do the changes? In _releases/v9.2.1/ or in release-source/?

[fatso83]

Release-source.

[danielrentz]

#2315