Update docs/how-to/hip_runtime_api/memory_management/host_memory.rst

Co-authored-by: MKKnorr <MKKnorr@web.de>

docs/how-to/hip_runtime_api/memory_management/host_memory.rst

@@ -9,12 +9,11 @@
 Host memory
 ********************************************************************************
 
-Host memory where on the host (e.g. CPU) of the machine in random access memory
-(RAM). The host memory has three different main types in HIP:
+Host memory is "normal" memory as allocated by C or C++, and resides in the RAM of the host.
+Host memory can be allocated in two different ways:
 
 * Pageable memory
 * Pinned memory
-* Unified Memory
 
 These different types of memory should be used at different use cases. The
 pageable and pinned memory using explicit memory management, where the