In the grammar for single-line-comment, do not require comments to be non-empty:
// single-line-comment-elem
=>
//

In the grammar for single-line-comment-elem, fix the category mismatch:
except line-break
=>
except a character that begins (and is the whole or a part of) a line-break

or "except a character that matches line-break-character"

In the grammar for multi-line-comment:
Apply "opt" to multi-line-comment-elem-seq.

In [lex.whitespaces]:
A disambiguation rule is required to prefer matching CRLF as a line-break instead of two line-breaks.

In the grammars for h-char and q-char, use whatever formulation was chosen for single-line-comment-elem.

Same comment for the grammars of basic-c-char and basic-s-char.

Same comment for the grammar of d-char. Additionally, use "a character that matches horizontal-whitespace-character" instead of the implied "a character that is horizontal-whitespace-character".

The [lex.string], the "line-break" in a raw string literal wording could be more explicit about scanning for line-breaks (sequences matching a line-break is not a line-break "for free"; it is a line-break if, for example, the grammar asks for a line-break).
This can be done by adding line-break under the r-char grammar and adjusting the other r-char case with the formula from single-line-comment-elem.

In [cpp.line]:
number of line-break
=>
number of line-breaks

In [lex.pptoken]:

This could be fixed by replacing:
each non-whitespace character that cannot be one of the above
=>
each character that cannot be considered part of a whitespace and cannot be one of the above

This also happens to fix a pre-existing issue that the wording is rather weak on preferring to interpret comments as comments.