pluralize doc comment verbs and add missing periods

src/libstd/dynamic_lib.rs

@@ -105,7 +105,7 @@ impl DynamicLibrary {
         }
     }
 
-    /// Access the value at the symbol of the dynamic library
+    /// Accesses the value at the symbol of the dynamic library.
     pub unsafe fn symbol<T>(&self, symbol: &str) -> Result<*mut T, String> {
         // This function should have a lifetime constraint of 'a on
         // T but that feature is still unimplemented