Fix default-trait-access

src/core/alloc/default.rs

@@ -2,8 +2,8 @@
 
 /// Always returns the empty string
 #[must_use]
-pub fn memory_stats() -> String { Default::default() }
+pub fn memory_stats() -> String { String::default() }
 
 /// Always returns the empty string
 #[must_use]
-pub fn memory_usage() -> String { Default::default() }
+pub fn memory_usage() -> String { String::default() }