add help builtins for special characters

[simonbyrne]

Help currently had a list of keywords that are handled specially:

julia/stdlib/REPL/src/docview.jl

Lines 524 to 529 in f806717

	const builtins = ["abstract type", "baremodule", "begin", "break",
	"catch", "ccall", "const", "continue", "do", "else",
	"elseif", "end", "export", "finally", "for", "function",
	"global", "if", "import", "let",
	"local", "macro", "module", "mutable struct", "primitive type",
	"quote", "return", "struct", "try", "using", "while"]

(from #12438).

It would be good to handle characters which have special meaning:

• $ for interpolation
• @ for macro invocation
• '' for character literals
• " for string literals
• [ for array expressions and comprehensions
• ( for tuples
• . for broadcasting
• ``` for commands
• ; other uses (as mentioned in punctuation.md)

cc: @charleskawczynski

[mbauman]

Some of these were just added in #33344 two weeks ago. I've converted your list into a checklist to track the remaining items.

I think the way to do it is through kw-docs like I did there, but I must confess I don't know how that builtins list works.

[mbauman]

The text for many of these can be pulled directly from https://github.com/JuliaLang/julia/blob/master/doc/src/base/punctuation.md, making this a great first issue.

[simonbyrne]

Ah, thanks!

[generationzcode]

hi I would like to help on this issue

[generationzcode]

so basically I have to add those characters "(" and "[" and many others into the array

[fingolfin]

Some more:

• the backtick ` for external command objects
• the docstring for ; is incomplete: it only mention that it can be used to delimit statements; IMHO, it should at least mention its other uses: to separate keyword arguments, and vcat. Indeed, doc/src/base/punctuation.md mentions all three.
• commas , separate function arguments or tuple or array components

[ArunS-tack]

I would like to take up this issue to update the documentation. I am new to Open Source and Julia. Any help would be appreciated.