docs: mention Terser instead of UglifyJS

Now that angular#11996 landed, the CLi uses Terser instead of UglifyJS.

Author: cexbrayat

docs/documentation/build.md

@@ -35,15 +35,15 @@ ng build --base-href /myUrl/
 ### Bundling & Tree-Shaking
 
 All builds make use of bundling and limited tree-shaking, while `--prod` builds also run limited
-dead code elimination via UglifyJS.
+dead code elimination via Terser.
 
 ### `--build-optimizer` and `--vendor-chunk`
 
 When using Build Optimizer the vendor chunk will be disabled by default.
 You can override this with `--vendor-chunk=true`.
 
 Total bundle sizes with Build Optimizer are smaller if there is no separate vendor chunk because
-having vendor code in the same chunk as app code makes it possible for Uglify to remove more unused
+having vendor code in the same chunk as app code makes it possible for Terser to remove more unused
 code.
 
 ### CSS resources
@@ -57,7 +57,7 @@ You'll see these resources be outputted and fingerprinted at the root of `dist/`
 
 To build in ES2015 mode, edit `./tsconfig.json` to use `"target": "es2015"` (instead of `es5`).
 
-This will cause application TypeScript and Uglify be output as ES2015, and third party libraries
+This will cause application TypeScript and Terser be output as ES2015, and third party libraries
 to be loaded through the `es2015` entry in `package.json` if available.
 
 Be aware that JIT does not support ES2015 and so you should build/serve your app with `--aot`.

packages/angular_devkit/build_optimizer/README.md

@@ -11,7 +11,7 @@ Transformations applied depend on file content:
 - [Import tslib](#import-tslib): applied when TypeScript helpers are found.
 
 Some of these optimizations add `/*@__PURE__*/` comments.
-These are used by [UglifyJS](https://github.com/mishoo/UglifyJS2) to identify pure functions that can potentially be dropped.
+These are used by [Terser](https://github.com/terser-js/terser) to identify pure functions that can potentially be dropped.
 
 
 ### Class fold