git-gui: Make the statistics of po2msg match those of msgfmt

The strings we were showing from po2msg didn't exactly match those
of msgfmt's --statistics output so we didn't show quite the same
results when building git-gui's message files.  Now we're closer
to what msgfmt shows (at least for an en_US locale) so the make
output matches.

I noticed that the fuzzy translation count is off by one for the
current po/zh_cn.po file.  Not sure why and I'm not going to try
and debug it at this time as the po2msg is strictly a fallback,
users building from source really should prefer msgfmt.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

po/po2msg.sh

@@ -127,7 +127,26 @@ foreach file $files {
 }
 
 if {$show_statistics} {
-	puts [concat "$translated_count translated messages, " \
-		"$fuzzy_count fuzzy ones, " \
-		"$not_translated_count untranslated ones."]
+	set str ""
+
+	append str  "$translated_count translated message"
+	if {$translated_count != 1} {
+		append str s
+	}
+
+	if {$fuzzy_count > 1} {
+		append str  ", $fuzzy_count fuzzy translation"
+		if {$fuzzy_count != 1} {
+			append str s
+		}
+	}
+	if {$not_translated_count > 0} {
+		append str  ", $not_translated_count untranslated message"
+		if {$not_translated_count != 1} {
+			append str s
+		}
+	}
+
+	append str  .
+	puts $str
 }