Update docs

docs/05-plugin-development.md

@@ -90,7 +90,7 @@ Kind: `async, parallel`<br>
 Previous Hook: [`options`](guide/en/#options)<br>
 Next Hook: [`resolveId`](guide/en/#resolveid) to resolve each entry point in parallel.
 
-Called on each `rollup.rollup` build. This is the recommended hook to use when you need access to the options passed to `rollup.rollup()` as it will take the transformations by all [`options`](guide/en/#options) hooks into account.
+Called on each `rollup.rollup` build. This is the recommended hook to use when you need access to the options passed to `rollup.rollup()` as it takes the transformations by all [`options`](guide/en/#options) hooks into account and also contains the right default values for unset options.
 
 #### `load`
 Type: `(id: string) => string | null | { code: string, map?: string | SourceMap, ast? : ESTree.Program, moduleSideEffects?: boolean | null, syntheticNamedExports?: boolean | null }`<br>
@@ -409,7 +409,7 @@ Kind: `async, parallel`<br>
 Previous Hook: [`outputOptions`](guide/en/#outputoptions)<br>
 Next Hook: [`banner`](guide/en/#banner), [`footer`](guide/en/#footer), [`intro`](guide/en/#intro) and [`outro`](guide/en/#outro) run in parallel.
 
-Called initially each time `bundle.generate()` or `bundle.write()` is called. To get notified when generation has completed, use the `generateBundle` and `renderError` hooks. This is the recommended hook to use when you need access to the output options passed to `bundle.generate()` or `bundle.write()` as it will take the transformations by all [`outputOptions`](guide/en/#outputoptions) hooks into account. It also receives the input options passed to `rollup.rollup()` so that plugins that can be used as output plugins, i.e. plugins that only use `generate` phase hooks, can get access to them.
+Called initially each time `bundle.generate()` or `bundle.write()` is called. To get notified when generation has completed, use the `generateBundle` and `renderError` hooks. This is the recommended hook to use when you need access to the output options passed to `bundle.generate()` or `bundle.write()` as it takes the transformations by all [`outputOptions`](guide/en/#outputoptions) hooks into account and also contains the right default values for unset options. It also receives the input options passed to `rollup.rollup()` so that plugins that can be used as output plugins, i.e. plugins that only use `generate` phase hooks, can get access to them.
 
 #### `resolveFileUrl`
 Type: `({chunkId: string, fileName: string, format: string, moduleId: string, referenceId: string, relativePath: string}) => string | null`<br>