Reword cargo add suggestion

Author: TrAyZeN

src/cargo/ops/cargo_install.rs

@@ -209,8 +209,7 @@ impl<'cfg, 'a> InstallablePackage<'cfg, 'a> {
             bail!(
                 "there is nothing to install in `{}`, because it has no binaries\n\
                  `cargo install` is only for installing programs, and can't be used with libraries.\n\
-                 To use a library crate, add it as a dependency in a Cargo project instead.\n\
-                 Use `cargo add {}` if you want to simply add it as a dependency of the current Cargo project.",
+                 To use a library crate, add it as a dependency to a Cargo project with `cargo add {}`.",
                 pkg,
                 pkg.name()
             );

tests/testsuite/install.rs

@@ -730,8 +730,7 @@ fn no_binaries() {
             "\
 [ERROR] there is nothing to install in `foo v0.0.1 ([..])`, because it has no binaries[..]
 [..]
-[..]
-Use `cargo add foo` if you want to simply add it as a dependency of the current Cargo project.",
+To use a library crate, add it as a dependency to a Cargo project with `cargo add foo`.",
         )
         .run();
 }