Add proposed Ukrainian wordlist (bitcoin/bips#442)

Notice:  This is hidden behind the -W flag; see 8aaa6f3.

This is not exactly the wordlist proposed in the pull request.  The file
ukrainian.txt from Bohdat/bips@152fc59 has a bug, in addition to the
usual normalization and sorting concerns:  A trailing space (0x20) and
tab (0x09, '\t') after the word at original index 1393, 1-based line
number 1394, and before the newline '\n'.  The problem was first
identified by failure of easyseed's extensive internal self-tests,
followed by examination of the problem with cmp(1) and hex dumps to
diagnose the difference between the wordlist in my source tree, and the
wordlist printed on stdout by `easyseed -W -P -l uk`.

The following is edited for line length limits in the git log, but it
adequately shows the problem:

$ grep -E '[[:space:]]$' ukrainian.txt | hd
00000000  d0 bf d1 96 d1 81 d0 bd  d1 8f 20 09 0a
$ grep -En '[[:space:]]$' ukrainian.txt
1394:пісня 	<*end of line is here*>

It is fixed with the following command:

$ sed -E -e 's/[[:space:]]+$//' < ukrainian.txt > ukfix1/uk_fixed0.txt

After verification that this command made no other changes, it is
normalized and sorted:

$ ls -l ukrainian.txt ukfix1/uk_fixed0.txt
-rw-r--r-- 1 user user 24550 Jan  7 21:26 ukfix1/uk_fixed0.txt
-rw-r--r-- 1 user user 24552 Jan  7 20:31 ukrainian.txt
$ diff -u3 ukrainian.txt ukfix1/uk_fixed0.txt
[...showing only the desired line changed...]
$ uconv -f utf-8 -t utf-8 -x '::nfkd;' < uk_fixed0.txt | \
	LC_ALL=C LANG=C sort -s > uk_fixed1.txt
$ mv -i uk_fixed1.txt ../../easyseed/wordlist/ukrainian.txt
mv: overwrite '../../easyseed/wordlist/ukrainian.txt'? y

(Note with ref to 234c66c:  When normalizing and sorting the russian.txt
list, I forgot to force the locale for `sort(1)`.  I verified that this
makes no difference, and the 234c66c russian.txt is correct.  It *does*
make a very large difference for the Ukrainian wordlist.)

SHA-256 hash for the resulting ukrainian.txt:
612ee29e1fa13dc38c9e1b31c7ef980db8f3c8dd30f1c9377170d1b10e895dc9

Makefile.inc

@@ -12,7 +12,8 @@ WORDLISTS=	chinese_simplified \
 		japanese \
 		korean \
 		russian \
-		spanish
+		spanish \
+		ukrainian
 
 VECTORSRC=	mkvectors.sh \
 		vectors.h \

easyseed.c

@@ -117,7 +117,8 @@ static const struct wordlist wordlists[] =
 	LANG(japanese,			u8"日本語",	"ja",	u8"\u3000",  1),
 	LANG(korean,			u8"한국어",	"ko",	ascii_space, 1),
 	LANG(russian,			u8"Русский",	"ru",	ascii_space, 0),
-	LANG(spanish,			u8"Español",	"es",	ascii_space, 1)
+	LANG(spanish,			u8"Español",	"es",	ascii_space, 1),
+	LANG(ukrainian,			u8"Українська",	"uk",	ascii_space, 0),
 };
 
 #undef LANG