fix(rolldown): correct exported type for Rolldown plugin

Closes #470

- Mark pluginFactory's Nested generic as false since it always returns
  a single plugin, never an array.
- Cast createRolldownPlugin result to Plugin<any> to fix Rolldown config
  type checking (the unplugin adapter's distributive conditional types
  produce Plugin | Plugin[] otherwise).

Author: qmhc

packages/unplugin-dts/src/core/utils.ts

@@ -32,6 +32,7 @@ export const jsRE = /\.([cm])?jsx?$/
 export const tsRE = /\.([cm])?tsx?$/
 export const dtsRE = /\.d\.([cm])?tsx?$/
 export const tjsRE = /\.([cm])?([jt])sx?$/
+// e.g. .ts .tsx .js .jsx .mts .mjs .cts .cjs
 export const mtjsRE = /\.m([jt])sx?$/
 export const ctjsRE = /\.c([jt])sx?$/
 export const fullRelativeRE = /^\.\.?\//

packages/unplugin-dts/src/plugin.ts

@@ -33,7 +33,7 @@ import type { Logger } from './core'
 const pluginName = 'unplugin:dts'
 const logPrefix = cyan(`[${pluginName}]`)
 
-export const pluginFactory: UnpluginFactory<PluginOptions | undefined> = /* #__PURE__ */ (
+export const pluginFactory: UnpluginFactory<PluginOptions | undefined, false> = /* #__PURE__ */ (
   options = {},
   meta,
 ) => {

packages/unplugin-dts/src/rolldown.ts

@@ -1,4 +1,7 @@
 import { createRolldownPlugin } from 'unplugin'
 import { pluginFactory } from './plugin'
 
-export default createRolldownPlugin(pluginFactory)
+import type { Plugin } from 'rolldown'
+import type { PluginOptions } from './types'
+
+export default createRolldownPlugin(pluginFactory) as (options?: PluginOptions) => Plugin<any>