Make all autonyms unique and add a test for this

In a list of languages to select autonyms must be unique so that
every user would know what to select.

* Batak Toba language in the Batak writing variant (bbc-batk) has
  an autonum in the right script now. This is taken from the Indonesian
  Wikipedia article "Surat Batak".
* Similarly to the practice with pa -> pa-guru:
  * iu for Inuktitut in the Canadian script redirects to ike-cans.
  * ks for Kashmiri in the Arabic writing redirects to ks-arab.
  * tg for Tajik in the Cyrillic script redirects to tg-cyrl.
* zgh has an updated autonym, taken from Ethologue.
* zh-classical redirects to lzh, similarly to zh-yue -> yue.

data/langdb.yaml

@@ -51,9 +51,8 @@ languages:
   bar: [Latn, [EU], Boarisch]
   bat-smg: [sgs]
   bbc-latn: [Latn, [AS], Batak Toba]
- # FIXME - autonym in the Batak script is unknown
-  bbc-batk: [Batk, [AS], Batak Toba]
-  bbc: [Latn, [AS], Batak Toba]
+  bbc-batk: [Batk, [AS], ᯅᯖᯂ᯲ ᯖᯬᯅ]
+  bbc: [bbc-latn]
   bcc: [Arab, [AS, ME], جهلسری بلوچی]
   bcl: [Latn, [AS], Bikol Central]
   be-tarask: [Cyrl, [EU], беларуская (тарашкевіца)]
@@ -228,8 +227,7 @@ languages:
   io: [Latn, [WW], Ido]
   is: [Latn, [EU], íslenska]
   it: [Latn, [EU], italiano]
- # For variants ike-* is used
-  iu: [Cans, [AM], ᐃᓄᒃᑎᑐᑦ]
+  iu: [ike-cans]
   ja: [Jpan, [AS], 日本語]
   jam: [Latn, [AM], Patois]
   jbo: [Latn, [WW], lojban]
@@ -279,7 +277,7 @@ languages:
   krl: [Latn, [EU], Karjala]
   ks-arab: [Arab, [AS], کٲشُر]
   ks-deva: [Deva, [AS], कॉशुर]
-  ks: [Arab, [AS], کٲشُر]
+  ks: [ks-arab]
   ksf: [Latn, [AF], Bafia]
   ksh: [Latn, [EU], Ripoarisch]
  # CLDR uses ku-latn and ku-arab. Latin is more common and is used in Wikipedia.
@@ -502,7 +500,7 @@ languages:
   tet: [Latn, [AS, PA], tetun]
   tg-cyrl: [Cyrl, [AS], тоҷикӣ]
   tg-latn: [Latn, [AS], tojikī]
-  tg: [Cyrl, [AS], тоҷикӣ]
+  tg: [tg-cyrl]
   th: [Thai, [AS], ไทย]
   ti: [Ethi, [AF], ትግርኛ]
   tig: [Ethi, [AF], ትግረ]
@@ -570,10 +568,10 @@ languages:
   yue: [Hant, [AS], 粵語]
   za: [Latn, [AS], Vahcuengh]
   zea: [Latn, [EU], Zeêuws]
-  zgh: [Tfng, [AF], ⵜⴰⵎⴰⵣⵉⵖⵜ]
+  zgh: [Tfng, [AF], ⵜⴰⵎⴰⵣⵉⵖⵜ ⵜⴰⵏⴰⵡⴰⵢⵜ]
  # world? (may apply to many varieties of Chinese)
   zh: [Hans, [AS], 中文]
-  zh-classical: [Hant, [AS], 文言]
+  zh-classical: [lzh]
   zh-cn: [Hans, [AS], 中文（中国大陆）]
   zh-hans: [Hans, [AS], 中文（简体）]
   zh-hant: [Hant, [AS], 中文（繁體）]