Fix grammar

[asztalosdani]

Why:

There was a grammar mistake in the strategy/matrix docs.

What's being changed (if available, include any code snippets, screenshots, or gifs):

Chaging that are based the combinations of the variables to that are based ON the combinations of the variables.

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[welcome]

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[cmwilson21]

@asztalosdani Thanks so much for opening a PR! I'll get this triaged for review ⚡

[mchammer01]

@asztalosdani - thanks for spotting this and fixing it ✨
LGTM 💖

[github-actions]

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