Change vm.max_map_count default to 1048576 in All ES docs for version 8.16+ (#4295)

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## Summary
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This is to address
elastic/docs-content-internal#592.

I am raising this as the first PR to decide the wording with docs, and
ES dev / PM team. Thanks!



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## Preview / View

### Before PR merge


[deploy-manage/deploy/self-managed/vm-max-map-count.md](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/4295/deploy-manage/deploy/self-managed/vm-max-map-count)

### After PR merge


https://www.elastic.co/docs/deploy-manage/deploy/self-managed/vm-max-map-count

---------

Co-authored-by: Vlada Chirmicci <[email protected]>

Author: kunisen

deploy-manage/deploy/self-managed/vm-max-map-count.md

@@ -10,12 +10,16 @@ products:
 
 # Increase virtual memory [vm-max-map-count]
 
-{{es}} uses a [`mmapfs`](elasticsearch://reference/elasticsearch/index-settings/store.md#mmapfs) directory by default to store its indices. The default operating system limits on mmap counts is likely to be too low, which may result in out of memory exceptions.
+{{es}} uses a [`mmapfs`](elasticsearch://reference/elasticsearch/index-settings/store.md#mmapfs) directory by default to store its indices. The default operating system limits on mmap counts could be too low, which may result in out of memory exceptions.
+
+:::{admonition} Verify vm.max_map_count configuration
+If the operating system's default `vm.max_map_count` value is `1048576` or higher, no configuration change is necessary. If the default value is lower than `1048576`, configure the `vm.max_map_count` parameter to `1048576`.
+:::
 
 On Linux, you can increase the limits by running the following command as `root`:
 
 ```sh
-sysctl -w vm.max_map_count=262144
+sysctl -w vm.max_map_count=1048576
 ```
 
 To set this value permanently, update the `vm.max_map_count` setting in `/etc/sysctl.conf`. To verify after rebooting, run `sysctl vm.max_map_count`.