doc: override optimization with STRICT

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/doc/changes.src b/doc/changes.src
index 4c0c305..05a2a55 100644
--- a/doc/changes.src
+++ b/doc/changes.src
@@ -16,6 +16,8 @@
 \c	mov r64,imm32			;  7 bytes
 \c	mov r64,imm64			; 10 bytes
 
+To force a specific form, use the \c{STRICT} keyword, see \k{strict}.
+
 
 \S{cl-2.09} Version 2.09