docs: documented 'memory_hexdump'

.wiki/Kernel-documentation.md

@@ -1252,6 +1252,10 @@ On linux this function is called _free_.
 #### `memory_allocator_init(base)` - function (void)
 This initializes the heap, where `memory_allocate` allocates memory.
 
+#### `memory_hexdump(address, num)` - function (void)
+Logs **_num_** bytes from **_address_** as 8 byte rows.
+The data is represented in hexadecimal and ascii.
+
 ### panic.h
 Ahhhhh - the kernel is burning!