bug#56870: company-dabbrev variable documentation

[YE]

> So I don't think there's anything to fix in Emacs here -- we sometimes
> say "the symbol `all'" if there's an unusual amount of possible
> confusion present -- and I'm therefore closing this bug report.

I'd still suggest considering documentation improvement in this regard.
Probably because I had the same confusion when started with Emacs, even
after having read the whole manual.

[Well, the info node `(elisp) Documentation Tips)' clarifies how to
document symbols :
>  When a documentation string refers to a Lisp symbol, write it as it
>      would be printed (which usually means in lower case), surrounding
>      it with curved single quotes (‘..’)
But Emacs beginner users don't seem to be the target auditory of this
page. And it still won't -- naturally -- explain how to _use_ such
symbols.]

One such possible place to adjust is the info node `(emacs) Examining'.
Maybe replace 'fill-column' example with the one that accepts a
documented symbol (f.i. 'default-justification', 'diff-refine',
'tab-always-complete') and use the symbol in the code below?

Another: info node `(emacs) Init Syntax' could probably state more
explicitly how to deal with the symbols.

Or mention symbols documentation/usage at the end of the info node
`(emacs) Variables', after the line "check the variable’s documentation
string to see what kind of value it expects".

WDYT?