koi8-u.7: Charset pages unification, minor cleanups

- adjust references
- remove stray comments, streamline description
  (charsets(7) and Wikipedia provide more detailed
   and up-to-date description)
- list differences between koi8-r.7 vs koi8-u.7
- cosmetics

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man7/koi8-u.7

@@ -25,24 +25,18 @@
 .\" 2009-01-15, mtk, Some edits
 .\"
 .TH KOI8-U 7 2014-03-18 "Linux" "Linux Programmer's Manual"
-.nh
 .SH NAME
-koi8-u \- Ukrainian character set encoded in octal, decimal, and
-hexadecimal
+koi8-u \- Ukrainian character set encoded in octal, decimal,
+and hexadecimal
 .SH DESCRIPTION
-KOI8-U (KOI8 Ukrainian, described in RFC\ 2310)
-is the de-facto standard character set for encoding Ukrainian texts.
-KOI8-U is compatible with KOI8-R (RFC 1489)
-for all Russian letters, and extends KOI8-R with four
-Ukrainian letters (in both uppercase and lowercase)
-in locations that are compliant with ISO-IR-111.
+RFC\ 2310 defines an 8-bit character set, KOI8-U.
+KOI8-U encodes the
+characters used in Ukrainian and Byelorussian.
 .SS KOI8-U characters
 The following table displays the characters in KOI8-U, which
 are printable and unlisted in the
 .BR ascii (7)
 manual page.
-.\" The fourth column will only show the proper glyphs
-.\" in an environment configured for koi8-u.
 .TS
 l l l c lp-1.
 Oct	Dec	Hex	Char	Description
@@ -193,4 +187,7 @@ The differences from KOI8-R are in the hex positions
 A4, A6, A7, AD, B4, B6, B7, and BD.
 .SH SEE ALSO
 .BR ascii (7),
-.BR koi8-r (7)
+.BR charsets (7),
+.BR iso_8859-5 (7),
+.BR koi8-r (7),
+.BR utf-8 (7)