doc: release/4.0: add bits about demand paging

This adds some bits about demand paging in release note
for 4.0.

Signed-off-by: Daniel Leung <[email protected]>

Author: dcpleung

doc/releases/release-notes-4.0.rst

@@ -79,6 +79,8 @@ Architectures
 
   * Added initial support for :c:func:`arch_stack_walk` that supports unwinding via esf only
 
+  * Added support for demand paging.
+
 * RISC-V
 
   * The stack traces upon fatal exception now prints the address of stack pointer (sp) or frame
@@ -502,6 +504,8 @@ Libraries / Subsystems
 
 * Demand Paging
 
+  * Added LRU (Least Recently Used) eviction algorithm.
+
 * Formatted output
 
 * Management