Remove redundant sentence. Send to nostarch

Fixes #3994.

src/ch07-01-packages-and-crates.md

@@ -33,12 +33,9 @@ build those crates. Cargo is actually a package that contains the binary crate
 for the command-line tool you’ve been using to build your code. The Cargo
 package also contains a library crate that the binary crate depends on. Other
 projects can depend on the Cargo library crate to use the same logic the Cargo
-command-line tool uses.
-
-A crate can come in one of two forms: a binary crate or a library crate. A
-package can contain as many binary crates as you like, but at most only one
-library crate. A package must contain at least one crate, whether that’s a
-library or binary crate.
+command-line tool uses. A package can contain as many binary crates as you
+like, but at most only one library crate. A package must contain at least one
+crate, whether that’s a library or binary crate.
 
 Let’s walk through what happens when we create a package. First we enter the
 command `cargo new my-project`: