doc: Update --max-semi-space-size description

Signed-off-by: Joe Bowbeer <joe.bowbeer@gmail.com>

doc/api/cli.md

@@ -3543,8 +3543,12 @@ an increase of 1 MiB to semi-space applies to each of the three individual
 semi-spaces and causes the heap size to increase by 3 MiB. The throughput
 improvement depends on your workload (see [#42511][]).
 
-The default value is 16 MiB for 64-bit systems and 8 MiB for 32-bit systems. To
-get the best configuration for your application, you should try different
+The default value depends on the memory limit. For example, on 64-bit systems
+with a memory limit of 512 MiB, the max size of a semi-space defaults to 1 MiB.
+On 64-bit systems with a memory limit of 2 GiB, the max size of a semi-space
+defaults to 16 MiB.
+
+To get the best configuration for your application, you should try different
 max-semi-space-size values when running benchmarks for your application.
 
 For example, benchmark on a 64-bit systems: