libzeth: small documentation fix

libzeth/core/utils.hpp

@@ -15,8 +15,10 @@
 namespace libzeth
 {
 
-/// Takes a container with a `size()` method and reverse the order
-/// of the elements. The elements should represent bits.
+/// Takes a container with a `size()` method containing a multiple of 8
+/// elements. The elements (considered to be bit-like) are divided into "bytes"
+/// (groups of 8), and the order of these "bytes" is reversed. The order of
+/// "bits" within each "byte" is preserved.
 template<typename T> T swap_byte_endianness(T v);
 
 /// Returns the binary encoding of the address of a leaf node in a binary tree.