Change names of Cyrillic-script languages to lowercase

They were added long ago when all the languages were
added in uppercase like English and German, but this
is not actually necessary.

data/langdb.yaml

@@ -5,7 +5,7 @@ languages:
   abs: [Latn, [AS], Bahasa Ambon]
   ace: [Latn, [AS, PA], Acèh]
   acf: [Latn, [AM], kwéyòl]
-  ady: [Cyrl, [EU, ME], Адыгабзэ]
+  ady: [Cyrl, [EU, ME], адыгабзэ]
   ady-cyrl: [ady]
   ady-latn: [Latn, [EU, ME], Adygabze]
   aeb: [aeb-arab]
@@ -150,7 +150,7 @@ languages:
   csb: [Latn, [EU], kaszëbsczi]
  # FIXME: which script to prefer?..
   cu: [Cyrl, [EU], словѣньскъ / ⰔⰎⰑⰂⰡⰐⰠⰔⰍⰟ]
-  cv: [Cyrl, [EU], Чӑвашла]
+  cv: [Cyrl, [EU], чӑвашла]
   cy: [Latn, [EU], Cymraeg]
   da: [Latn, [EU], dansk]
   dag: [Latn, [AF], dagbanli]
@@ -275,7 +275,7 @@ languages:
   ike-cans: [Cans, [AM], ᐃᓄᒃᑎᑐᑦ]
   ike-latn: [Latn, [AM], inuktitut]
   ilo: [Latn, [AS], Ilokano]
-  inh: [Cyrl, [EU], ГӀалгӀай]
+  inh: [Cyrl, [EU], гӀалгӀай]
   io: [Latn, [WW], Ido]
   is: [Latn, [EU], íslenska]
   it: [Latn, [EU], italiano]
@@ -298,7 +298,7 @@ languages:
   kac: [Latn, [AS], Jinghpaw]
   kbd-cyrl: [kbd]
   kbd-latn: [Latn, [EU], Qabardjajəbza]
-  kbd: [Cyrl, [EU, ME], Адыгэбзэ]
+  kbd: [Cyrl, [EU, ME], адыгэбзэ]
   kbp: [Latn, [AF], Kabɩyɛ]
   kcg: [Latn, [AF], Tyap]
   kea: [Latn, [AF], kabuverdianu]
@@ -345,7 +345,7 @@ languages:
   kum: [Cyrl, [EU], къумукъ]
   kv: [Cyrl, [EU], коми]
   kw: [Latn, [EU], kernowek]
-  ky: [Cyrl, [AS], Кыргызча]
+  ky: [Cyrl, [AS], кыргызча]
   la: [Latn, [EU], Latina]
   lad: [lad-latn]
   lad-latn: [Latn, [ME, EU, AM], Ladino]
@@ -456,7 +456,7 @@ languages:
   om: [Latn, [AF], Oromoo]
   ood: [Latn, [AM], "ʼOʼodham ha-ñeʼokĭ"]
   or: [Orya, [AS], ଓଡ଼ିଆ]
-  os: [Cyrl, [EU], Ирон]
+  os: [Cyrl, [EU], ирон]
   osi: [Latn, [AS], Using]
  # Bug: 60815
   ota: [Arab, [AS, EU], لسان عثمانى]
@@ -602,7 +602,7 @@ languages:
   ti: [Ethi, [AF], ትግርኛ]
   tig: [Ethi, [AF], ትግረ]
   tk: [Latn, [AS], Türkmençe]
-  tkr: [Cyrl, [AS], ЦӀаӀхна миз]
+  tkr: [Cyrl, [AS], цӀаӀхна миз]
   tl: [Latn, [AS], Tagalog]
   tly: [Latn, [EU, AS, ME], tolışi]
   tly-cyrl: [Cyrl, [EU, AS, ME], толыши]
@@ -662,7 +662,7 @@ languages:
   ydd: [Hebr, [AS, EU], Eastern Yiddish]
   yi: [Hebr, [ME, EU, AM], ייִדיש]
   yo: [Latn, [AF], Yorùbá]
-  yrk: [Cyrl, [AS], Ненэцяʼ вада]
+  yrk: [Cyrl, [AS], ненэцяʼ вада]
   yrl: [Latn, [AM], "ñe'engatú"]
   yua: [Latn, [AM], "Maaya T'aan"]
   yue: [Hant, [AS], 粵語]

data/language-data.json

@@ -49,7 +49,7 @@
                 "EU",
                 "ME"
             ],
-            "Адыгабзэ"
+            "адыгабзэ"
         ],
         "ady-cyrl": [
             "ady"
@@ -902,7 +902,7 @@
             [
                 "EU"
             ],
-            "Чӑвашла"
+            "чӑвашла"
         ],
         "cy": [
             "Latn",
@@ -1750,7 +1750,7 @@
             [
                 "EU"
             ],
-            "ГӀалгӀай"
+            "гӀалгӀай"
         ],
         "io": [
             "Latn",
@@ -1890,7 +1890,7 @@
                 "EU",
                 "ME"
             ],
-            "Адыгэбзэ"
+            "адыгэбзэ"
         ],
         "kbp": [
             "Latn",
@@ -2184,7 +2184,7 @@
             [
                 "AS"
             ],
-            "Кыргызча"
+            "кыргызча"
         ],
         "la": [
             "Latn",
@@ -2944,7 +2944,7 @@
             [
                 "EU"
             ],
-            "Ирон"
+            "ирон"
         ],
         "osi": [
             "Latn",
@@ -3906,7 +3906,7 @@
             [
                 "AS"
             ],
-            "ЦӀаӀхна миз"
+            "цӀаӀхна миз"
         ],
         "tl": [
             "Latn",
@@ -4317,7 +4317,7 @@
             [
                 "AS"
             ],
-            "Ненэцяʼ вада"
+            "ненэцяʼ вада"
         ],
         "yrl": [
             "Latn",