[src/doc/book] Use package registry for crates.io

Author: behnam

src/doc/book/src/02-04-dependencies.md

@@ -1,8 +1,8 @@
-## Adding dependencies from crates.io
+## Dependencies
 
-[crates.io] is the Rust community's central repository that serves
-as a location to discover and download packages. `cargo` is configured to use
-it by default to find requested packages.
+[crates.io] is the Rust community's central package registry that serves as a
+location to discover and download packages. `cargo` is configured to use it by
+default to find requested packages.
 
 To depend on a library hosted on [crates.io], add it to your `Cargo.toml`.
 

src/doc/guide.md

@@ -131,9 +131,9 @@ project.
 
 # Adding dependencies from crates.io
 
-[crates.io] is the Rust community's central repository that serves
-as a location to discover and download packages. `cargo` is configured to use
-it by default to find requested packages.
+[crates.io] is the Rust community's central package registry that serves as a
+location to discover and download packages. `cargo` is configured to use it by
+default to find requested packages.
 
 To depend on a library hosted on [crates.io], add it to your `Cargo.toml`.