added missing comma in code example in Advanced > Composition API > Basic Usage to prevent copy paste compiler errors (#640)

Co-authored-by: Luca <[email protected]>

Author: Topograph

docs/guide/advanced/composition.md

@@ -19,7 +19,7 @@ The following is an example of adding the `legacy` option to `createI18n`:
 const i18n = VueI18n.createI18n({
   legacy: false, // you must set `false`, to use Composition API
   locale: 'ja', // set locale
-  fallbackLocale: 'en' // set fallback locale
+  fallbackLocale: 'en', // set fallback locale
   messages, // set locale messages
   // If you need to specify other options, you can set other options
   // ...

docs/ja/guide/advanced/composition.md

@@ -19,7 +19,7 @@ The following is an example of adding the `legacy` option to `createI18n`:
 const i18n = VueI18n.createI18n({
   legacy: false, // you must set `false`, to use Composition API
   locale: 'ja', // set locale
-  fallbackLocale: 'en' // set fallback locale
+  fallbackLocale: 'en', // set fallback locale
   messages, // set locale messages
   // If you need to specify other options, you can set other options
   // ...