fix: param name for missing in setupI18nProps (#1411)

packages/core/src/i18n.ts

@@ -53,12 +53,16 @@ export type MissingMessageEvent = {
   context?: string
 }
 
+type MissingHandler =
+  | string
+  | ((locale: string, id: string, context: string) => string)
+
 type setupI18nProps = {
   locale?: Locale
   locales?: Locales
   messages?: AllMessages
   localeData?: AllLocaleData
-  missing?: string | ((message: string, id: string, context: string) => string)
+  missing?: MissingHandler
 }
 
 type Events = {
@@ -71,7 +75,7 @@ export class I18n extends EventEmitter<Events> {
   private _locales: Locales
   private _localeData: AllLocaleData
   private _messages: AllMessages
-  private _missing: string | ((message, id, context) => string)
+  private _missing: MissingHandler
 
   constructor(params: setupI18nProps) {
     super()

website/docs/ref/core.md

@@ -289,13 +289,13 @@ const i18n = setupI18n({ missing: "🚨" })
 i18n._('missing translation') === "🚨"
 ```
 
-This might be also a function which is called with active language and message ID:
+This might be also a function which is called with active locale and message ID:
 
 ``` jsx
 import { setupI18n } from "@lingui/core"
 
-function missing(language, id) {
-   alert(`Translation in ${language} for ${id} is missing!`)
+function missing(locale, id) {
+   alert(`Translation in ${locale} for ${id} is missing!`)
    return id
 }