Tweak NEWS so some additional issue numbers become links in html version.
whatsnew: Wave_write handles unseekable files. (#5202)

Also clarify the documentation of this feature.
whatsnew: sunau/aifc/wave writeframes[raw] accept any bytes-like (#8311)
whatsnew: dbm.open is context manager. (#19282)
whatsnew: base65 encodings. (#17618)

Also updated the base64 module title and introduction to adjust for
the fact that these new encodings are included.

Also adjusted the wording about the base64 alphabets (see
issue #20837).
whatsnew: glob.escape.
whatsnew: tidy up html notes, add porting note for expand_charrefs.