Add doc comment for resolve_hir_path_qualifier

crates/ra_hir/src/semantics.rs

@@ -452,6 +452,19 @@ impl<'a, DB: HirDatabase> SemanticsScope<'a, DB> {
         resolve_hir_path(self.db, &self.resolver, path)
     }
 
+    /// Resolves a path where we know it is a qualifier of another path.
+    ///
+    /// For example, if we have:
+    /// ```
+    /// mod my {
+    ///     pub mod foo {
+    ///         struct Bar;
+    ///     }
+    ///
+    ///     pub fn foo() {}
+    /// }
+    /// ```
+    /// then we know that `foo` in `my::foo::Bar` refers to the module, not the function.
     pub fn resolve_hir_path_qualifier(&self, path: &Path) -> Option<PathResolution> {
         resolve_hir_path_qualifier(self.db, &self.resolver, path)
     }