Remove double spaces

[felixpernegger]

Changes . to .

Arguably not the most important PR, but this improves the style slightly.
I went over the changes (briefly) and it looks good.

[prabau]

Not sure why we are doing this. I am probably one of the people who used double spaces here. I think they help separate sentences from each other within a paragraph when in a monospace environment, for example in an editor like vscode. And the end result on a web page is identical.

[felixpernegger]

I mean it would show up as a mistake in spell checks I think. I really haven't seen double spaces used in any "code" (or text) anywhere, so I think this is the better way (nowadays). Furthermore, . isnt used consistently at all (even in the same paragraphs as witnessed in this PR), so why not stay consistent.

Nonetheless, this is obviously a very minor change, so whatever...

[prabau]

I have never seen any spell checker complain about this.

On the other hand, if everybody here thinks that should be the standard, we should add it to the pi-base wiki as a style guideline, and I will follow it in the future. Otherwise, not.

@StevenClontz we need your input here.

[StevenClontz]

I don't think we should need a policy here one way or the other for now.

If we want one, I'd ask for three things:

1. A linter that checks for this on every PR, and puts up a red X so we know to fix the new contribution.
2. A bot that makes the fix and proposes it to the PR that an editor can merge in automatically.
3. An enhancement to the pi-Base VS Code plugin that automatically fixes the spacing after fullstops upon save (and marks incorrect usage with a blue squiggle underline).

With respect to all parties, I'm going to close this PR for now, but anyone is welcome to reopen if they feel strongly that conversation should continue.

(Personally, I am Team Single-Space -- it should be the job of the software, not the author, to make things look "good" in the software interface. But if we had all of the above set up, I wouldn't care which one decide is "right", unless I guess someone can prove that double-spacing adds a significant amount of extra size to our data blobs.)

[prabau]

Thanks Steven. Personally, I think 1, 2, 3 is overkill. If everyone here is in Team Single-Space, there shouldn't be a problem in adding a "recommendation" in the pi-base wiki. And I would follow that recommendation. So, if anyone strongly cares, please follow up and get consensus on it. Otherwise, it will remain as is.