bug#15797: 24.3.50; Info: Mention cache-long-scans

[Jambunathan K]

Why is this variable in lispref.  The variable deserves atleast a
mention in the main manual.

Glenn Morris <rgm@gnu.org> writes:

> cd doc
> find . -name '*.texi' -exec grep 'cache-long.*scans' {} +
>
> ./lispref/display.texi:@code{cache-long-scans} to @code{t}.
> ./lispref/display.texi:@defvar cache-long-scans
> ./lispref/positions.texi:performance of your code.  @xref{Truncation,
> cache-long-scans}.
>
> So: cache-long-scans is defined, and there are no references to the old
> name cache-long-line-scans.