docs: Document build config options

Author: lachlancollins

src/build/index.d.ts

@@ -1,8 +1,11 @@
 import type { UserConfig } from 'vite'
 
 export type Options = {
+  /** Entry file, e.g. `./src/index.ts` */
   entry: string | string[]
+  /** Source directory used for type generation, e.g. `./src` */
   srcDir: string
+  /** Excluded from type generation, e.g. `[./src/tests]` */
   exclude?: string[]
 }