Be more precise in the description of register_dep

Author: Chris00

src/lib.rs

@@ -275,8 +275,11 @@ impl Config {
     /// Registers a dependency for this compilation on the native library built
     /// by Cargo previously.
     ///
-    /// This registration will modify the `CMAKE_PREFIX_PATH` environment
-    /// variable for the build system generation step.
+    /// This registration will add the path in the environment
+    /// variable `DEP_XXX_ROOT`, where `XXX` is replaced with the
+    /// uppercased value of `dep`, to the `CMAKE_PREFIX_PATH`
+    /// environment variable for the [`build`][Self::build] system
+    /// generation step.
     pub fn register_dep(&mut self, dep: &str) -> &mut Config {
         self.deps.push(dep.to_string());
         self