Fix this.resolve return type in docs (#3825)

docs/05-plugin-development.md

@@ -668,7 +668,7 @@ An object containing potentially useful Rollup metadata:
 
 Use Rollup's internal acorn instance to parse code to an AST.
 
-#### `this.resolve(source: string, importer?: string, options?: {skipSelf?: boolean, custom?: {[plugin: string]: any}}) => Promise<{id: string, external: boolean, moduleSideEffects: boolean | 'no-treeshake', syntheticNamedExports: boolean | string, custom: {[plugin: string]: any}} | null>`
+#### `this.resolve(source: string, importer?: string, options?: {skipSelf?: boolean, custom?: {[plugin: string]: any}}) => Promise<{id: string, external: boolean, moduleSideEffects: boolean | 'no-treeshake', syntheticNamedExports: boolean | string, meta: {[plugin: string]: any}} | null>`
 Resolve imports to module ids (i.e. file names) using the same plugins that Rollup uses, and determine if an import should be external. If `null` is returned, the import could not be resolved by Rollup or any plugin but was not explicitly marked as external by the user.
 
 If you pass `skipSelf: true`, then the `resolveId` hook of the plugin from which `this.resolve` is called will be skipped when resolving.