feat: dprint formatter (denoland/deno#3820)

* rewrite fmt_test in Rust, remove tools/fmt_test.py
* remove //prettier

README.md

@@ -39,7 +39,6 @@ Here are the dedicated documentations of modules:
 - [http](http/README.md)
 - [log](log/README.md)
 - [media_types](media_types/README.md)
-- [prettier](prettier/README.md)
 - [strings](strings/README.md)
 - [testing](testing/README.md)
 - [uuid](uuid/README.md)

manual.md

@@ -847,7 +847,7 @@ $ echo 'export PATH="$HOME/.deno/bin:$PATH"' >> ~/.bashrc
 Installation directory can be changed using `-d/--dir` flag:
 
 ```shell
-$ deno install --dir /usr/local/bin prettier https://deno.land/std/prettier/main.ts --allow-write --allow-read
+$ deno install --dir /usr/local/bin file_server https://deno.land/std/http/file_server.ts --allow-net --allow-read
 ```
 
 When installing a script you can specify permissions that will be used to run
@@ -857,13 +857,11 @@ additional CLI flags you want to pass to the script.
 Example:
 
 ```shell
-$ deno install format_check https://deno.land/std/prettier/main.ts --allow-write --allow-read --check --print-width 88 --tab-width 2
+$ deno install file_server https://deno.land/std/http/file_server.ts --allow-net --allow-read 8080
 ```
 
-Above command creates an executable called `format_check` that runs `prettier`
-with write and read permissions. When you run `format_check` deno will run
-prettier in `check` mode and configured to use `88` column width with `2` column
-tabs.
+Above command creates an executable called `file_server` that runs with write
+and read permissions and binds to port 8080.
 
 It is a good practice to use `import.meta.main` idiom for an entry point for
 executable file. See