Tiny readability tweaks

[MarciaRieferJohnston]

This beautifully written page ("What’s the difference between a tutorial and how-to guide?") has furthered my understanding of a distinction I've held fuzzily for many years. Thank you.

[MarciaRieferJohnston]

@evildmp Hi, Daniele. I've just listened to your Write the Docs talk Always complete, never finished. Good stuff. Now I'm enjoying your Diátaxis site, which does a particularly helpful job of distinguishing task-oriented how-to documentation from learning-oriented tutorials.

Please review and approve these tweaks for readability if you agree with them.