[atomics.ref.pointer] Do not refer to T

[dalg24]

Fixes https://github.com/cplusplus/nbballot/issues/888

cc @jwakely

[tkoeppe]

Please update commit messages to contain the standard "Fixes NB ..." phrase (see other commits).

[jwakely]

LWG determined this is editorial, because there's no T in scope here and what we care about is being able to do arithmetic on some pointer-type which requires knowing the sizeof the pointee type. The edit matches what LWG asked for.

[tkoeppe]

@dalg24 Close enough :-)

[dalg24]

@dalg24 Close enough :-)

Yeah sorry I noticed I had the wrong message but I had another branch checked out and was planning to fix it again later.