[TASK] Allow whitepace parsing to be stopped at EOL

[JakeQZ]

The whitespace parsing includes extraction of comments to be associated with the content.

There are cases where the comment is after the content, but should be associated with the preceding rather than the following. This will help achieve that.

[coveralls]

coverage: 73.023% (+0.04%) from 72.984%
when pulling e1a0e9b on task/parse-comments-at-eol
into 252bbe1 on main.

[oliverklee]

I don't quite understand this yet: Why should consuming whitespace stop at a linefeed, i.e., what makes the linefeed whitespace character special?

[JakeQZ]

I don't quite understand this yet: Why should consuming whitespace stop at a linefeed, i.e., what makes the linefeed whitespace character special?

It's so we would be able to correctly attribute comments to the relevant declarations as 'before' and 'after' (or 'leading' and 'trailing'), e.g.

/* This is a comment about the font size. */
font-size: 14px;
color: green; /* This is a trailing comment about the colour.  It has nothing to do with the width. */
/* This is a comment about the width. */
width: 50%;

So after parsing a property declaration, we can consume whitespace and any trailing comments up to the next line feed. Then we parse the next property declaration, consuming possibly more whitespace and any leading comments.

It's a building block towards solving #663 and #1445.