This is to be consistent with other manuals:
- no period punctuation at end
- no capitalization at beginning unless acronym or proper noun
- and no simple article (like "A") to start sentence.
While the docbook specification says refpurpose is a "one sentence",
its examples show it with the rules shown above.
Also compared with many manpages as this is common format for the
.Nd macro's one line description.
f02194c053