fix(default): Clarify the installation procedure

default_out.txt

@@ -7,12 +7,13 @@ Let's make sure you're up to speed:
 - You have `~/.cargo/bin` added to your PATH variable
 - You have cloned this repository (https://github.com/rust-lang/rustlings)
 - You have installed Rust language support for your editor
-- You have locally installed the `rustlings` command by running:
+- You have locally installed the `rustlings` command by running an
+  installation script or manually executing:
 
 cargo install --force --path .
 
 If you've done all of this (or even most of it), congrats! You're ready
 to start working with Rust.
 
 To get started, run `rustlings watch` in order to get the first exercise.
-Make sure to have your editor open!
+Make sure to have your editor open!