Locale code for Twi is tw, twi.po -> tw.po

docs/html/OPTIONS.html

@@ -2304,7 +2304,7 @@ New Breed Software</p>
     <td>&nbsp;</td>
   </tr>
   <tr>
-    <td><code>twi_GH</code></td>
+    <td><code>tw_GH</code></td>
     <td>&nbsp;</td>
     <td>Twi</td>
     <td>&nbsp;</td>

src/i18n.c

@@ -158,7 +158,7 @@ const char *lang_prefixes[NUM_LANGS] = {
   "th",
   "tl",
   "tr",
-  "twi",
+  "tw",
   "uk",
   "ve",
   "vec",
@@ -374,7 +374,7 @@ static const language_to_locale_struct language_to_locale_array[] = {
   {"thai", "th_TH.UTF-8"},
   {"tibetan", "bo_CN.UTF-8"},	/* Based on: http://texinfo.org/pipermail/texinfo-pretest/2005-April/000334.html */
   {"turkish", "tr_TR.UTF-8"},
-  {"twi", "twi_GH.UTF-8"},
+  {"twi", "tw_GH.UTF-8"},
   {"ukrainian", "uk_UA.UTF-8"},
   {"walloon", "wa_BE.UTF-8"},
   {"walon", "wa_BE.UTF-8"},
@@ -636,7 +636,7 @@ static void show_locale_usage(FILE * f, const char *const prg)
 	  "  bo_CN   (Tibetan)\n"
 	  "  th_TH   (Thai)\n"
 	  "  tr_TR   (Turkish)\n"
-          "  twi_GH  (Twi)\n"
+          "  tw_GH  (Twi)\n"
           "  uk_UA   (Ukrainian)\n"
           "  ve_ZA   (Venda)\n"
           "  vec     (Venetian)\n"

src/i18n.h

@@ -144,7 +144,7 @@ enum
   LANG_TH,			/* Thai */
   LANG_TL,			/* Tagalog */
   LANG_TR,			/* Turkish */
-  LANG_TWI,			/* Twi */
+  LANG_TW,			/* Twi */
   LANG_UK,			/* Ukrainian */
   LANG_VE,			/* Venda */
   LANG_VEC,			/* Venetian */