minor copy edits and formatting for Getting Started

[cormullion]

I was planning on a pass through the Julia manual doing some copy-editing. The instructions said I must do a make docs build before making a PR. However, I tried this and after an hour or two it died in a blizzard of complaints about Fortran and OpenBLAS...

So this PR hasn't been tested with make docs. I'll make this one PR, just in case it contains anything worth preserving.

Edit: fix #26463

[waldyrious]

I appreciate the more explicit phrasing, but I wonder what benefit mentioning the ^ key brings here. I thought the caret notation was purely symbolic; are there input systems with an actual "^" key used for producing control characters?

FWIW, I actually just tried literally typing ^D (^, Space, Shift+D), ^d (^, Space, D), and combinations I expected to produce ̂D (^, Shift+D) and ̂d (^, D) in the julia prompt (v0.6.0 if it matters), as well as (^+Shift+D), and none of this worked. For context, I'm using a Portuguese keyboard layout which has a ̂~ key that produces combined characters like "ã" and "â" (using shift), unless a space is typed after the caret key, in which case I get "~a" and "^a". Perhaps @stevengj can provide commentary here regarding whether my input methods may have interfered.

[cormullion]

I think it's always 'ctrl' (or 'control') on Mac keyboards, but in menus and documentation people nearly always use ⌃ (U+2303) or something similar, but that could be mistaken for an up arrow. You can get fonts to show keys, but I wouldn't know whether that's a good idea to rely on it. Images would be a bit more explicit: not but , although keyboards vary a lot...

[waldyrious]

Just to make sure we're on the same page: are you saying that there are indeed physical "^" keys in keyboards, or that there are not, but people tend to represent the control character in documentation as if such keys existed (as a shortcut, I suppose, the same way Emacs/Vim use C-x)?

[cormullion]

1: Yes

2: they do.

[waldyrious]

Ah, got it. Thanks for clarifying.

[KristofferC]

Arguments to the file sounds good to me?

[cormullion]

I clarified my intentions a bit... :)

[fredrikekre]

You can replace this full code block with:

```@eval
io = IOBuffer()
Base.banner(io)
banner = String(take!(io))
import Markdown
Markdown.parse("""
```
\$ julia

$(banner)
julia> 1 + 2
3

julia> ans
3
```
""")
```

and this will be generated when the docs are built and we never have to update this manually again (:tada: )

[cormullion]

Great idea!

[KristofferC]

Failed to evaluate `@eval` block.

ERROR: ErrorException("syntax: incomplete: invalid string syntax")

[fredrikekre]

Good thing we have Documenter running in strict mode. Oh wait, someone turned that off in 87913c6

[fredrikekre]

Okay, this works locally

```@eval
io = IOBuffer()
Base.banner(io)
banner = String(take!(io))
import Markdown
Markdown.parse("```\n\$ julia\n\n$(banner)\njulia> 1 + 2\n3\n\njulia> ans\n3\n```")
```

[KristofferC]

Good thing you are working on adding it back ;)

Fixed

[cormullion]

Do I need to do anything more towards this?

[KristofferC]

I think the previous way was better (see e.g. dotnet/roslyn#216)

[KristofferC]

I changed back the digit separator to the previous version and merged. Hope that was ok.