bootstrap readme: make easy to read when editor wrapping is not enabled

This also makes it more consistent with other text in the file

Author: tshepang

src/bootstrap/README.md

@@ -221,7 +221,10 @@ please file issues on the [Rust issue tracker][rust-issue-tracker].
 
 ## Testing
 
-To run bootstrap tests, execute `x test bootstrap`. If you want to bless snapshot tests, then install `cargo-insta` (`cargo install cargo-insta`) and then run `cargo insta review --manifest-path src/bootstrap/Cargo.toml`.
+To run bootstrap tests, execute `x test bootstrap`.
+If you want to bless snapshot tests,
+then install `cargo-insta` (`cargo install cargo-insta`),
+and then run `cargo insta review --manifest-path src/bootstrap/Cargo.toml`.
 
 ## Changelog