Renamed yarn translate:portal to yarn translate:generate

refs https://github.com/TryGhost/Ghost/issues/15502

- needed to add the `i18n` tests so we don't lose the "Hello" test I
  wrote, and keeping everything under one command is easier

ghost/i18n/locales/en.json

@@ -1 +1,3 @@
-{}
+{
+    "Hello": "Hello"
+}

ghost/i18n/package.json

@@ -9,11 +9,11 @@
     "dev": "echo \"Implement me!\"",
     "test:unit": "NODE_ENV=testing c8 --include index.js --include lib --check-coverage --100  --reporter text --reporter cobertura mocha './test/**/*.test.js'",
     "test": "yarn test:unit && yarn test:translate",
-    "test:translate": "yarn translate:portal",
+    "test:translate": "yarn translate:generate",
     "lint:code": "eslint *.js lib/ --ext .js --cache",
     "lint": "yarn lint:code && yarn lint:test",
     "lint:test": "eslint -c test/.eslintrc.js test/ --ext .js --cache",
-    "translate:portal": "i18next '../portal/src/**/*.{js,jsx}'"
+    "translate:generate": "i18next '../portal/src/**/*.{js,jsx}' './test/**/*.js'"
   },
   "files": [
     "index.js",