fix: lint

Author: wan2land

formatter.ts

@@ -23,7 +23,7 @@ export class Formatter {
     this.plugin = options.plugin ?? {};
   }
 
-  format(text: string, parameters: FormatParameters = {}) {
+  format(text: string, parameters: FormatParameters = {}): string {
     return this.runtime.execute(
       text,
       parameters,

intlit.ts

@@ -17,7 +17,7 @@ export class Intlit<Messages extends Record<string, string>> {
   format<MessageId extends keyof Messages>(
     text: MessageId,
     parameters: FormatParameters = {},
-  ) {
+  ): string {
     return this.formatter.format(this.messages[text] ?? text, parameters);
   }
 }