man page pass, minor cleanups

man page pass, minor cleanups

SCCS-vsn: lib/libc/stdio/fgetln.3 5.3
SCCS-vsn: lib/libc/stdio/fgets.3 6.7
SCCS-vsn: lib/libc/stdio/fread.3 6.4
SCCS-vsn: lib/libc/stdio/fseek.3 6.7
SCCS-vsn: lib/libc/stdio/getc.3 6.5
SCCS-vsn: lib/libc/stdio/mktemp.3 6.8
SCCS-vsn: lib/libc/string/strerror.3 6.5
SCCS-vsn: lib/libc/stdio/printf.3 6.9
SCCS-vsn: lib/libc/stdio/setbuf.3 6.7
SCCS-vsn: lib/libc/stdio/stdio.3 6.4