Update superpowers.md

src/advance/unsafe/superpowers.md

@@ -70,7 +70,7 @@ fn get_memory_location() -> (usize, usize) {
   (pointer, length)
 }
 
-// 在制定的内存地址读取字符串
+// 在指定的内存地址读取字符串
 fn get_str_at_location(pointer: usize, length: usize) -> &'static str {
   unsafe { from_utf8_unchecked(from_raw_parts(pointer as *const u8, length)) }
 }