[docs/reference] more fixes in Markdown files

[michelou]

Follow up of PR #10767 and PR #10826.

Fixes more issues found in Markdown files in docs/reference/, e.g,

• removed extra spaces/lines
• corrected misspellings (e.g "toplevel" -> "top-level")
• corrected left margin in code block
• reduced line width in several code blocks (to avoid text overflow in the right margin)
• added several external links (e.g. alpha renaming)

PS. The above changes can also be viewed in the PDF document scala3_reference.pdf (734 Kb) generated with Pandoc 2.11.

[liufengyun]

LGTM, thanks @michelou 👍

[liufengyun]

This seems to be not necessary, as .value indeed exists in stdlib.

[michelou]

It comes from @nicolasstucki's suggestion (see his comment in PR #10826).

[liufengyun]

Maybe change it to something like the following:

In the above, the method .value maps a constant expression of the type Expr[T] to its value of the type T.

[michelou]

Done (see below).

[michelou]

@SethTisue I bet you will like the following changes in scala3_reference.pdf :

• The structure of the generated PDF document is now identical to the Online Reference documentation
  (I've moved the "More details" sections to the appendix).
• The title of each chapter ends with an external link to the corresponding chapter in the online Reference documentation.

[SethTisue]

@michelou I would like to tweet about the existence of this PDF. Should I use the https://github.com/michelou/dotty-examples/blob/master/docs/scala3_reference.pdf URL, or is there a plan to have it live in a more "official" location?

[michelou]

@SethTisue I have another PR pending. Again I will assign @liufengyun as reviewer and I will ask him to rule on a more "official" location.
NB. By the way I have no idea what are the plans regarding PDF documentation in general at the Scala Center.