Add cpx with three variants

Has been used on translatewiki for a while.

data/langdb.yaml

@@ -159,6 +159,10 @@ languages:
   co: [Latn, [EU], corsu]
   cop: [Copt, [AF, ME], ϯⲙⲉⲧⲣⲉⲙⲛ̀ⲭⲏⲙⲓ]
   cps: [Latn, [AS], Capiceño]
+  cpx-hans: [Hans, [AS], 莆仙语（简体）]
+  cpx-hant: [Hant, [AS], 莆仙語（繁體）]
+  cpx-latn: [Latn, [AS], Pó-sing-gṳ̂ (Báⁿ-uā-ci̍)]
+  cpx: [cpx-hant]
   cr: [Cans, [AM], ᓀᐦᐃᔭᐍᐏᐣ]
   cr-cans: [cr]
   cr-latn: [Latn, [AM], Nēhiyawēwin]

data/language-data.json

@@ -947,6 +947,30 @@
             ],
             "Capiceño"
         ],
+        "cpx-hans": [
+            "Hans",
+            [
+                "AS"
+            ],
+            "莆仙语（简体）"
+        ],
+        "cpx-hant": [
+            "Hant",
+            [
+                "AS"
+            ],
+            "莆仙語（繁體）"
+        ],
+        "cpx-latn": [
+            "Latn",
+            [
+                "AS"
+            ],
+            "Pó-sing-gṳ̂ (Báⁿ-uā-ci̍)"
+        ],
+        "cpx": [
+            "cpx-hant"
+        ],
         "cr": [
             "Cans",
             [