add `platform-split` parameter (#22753)

<!--Delete sections as needed -->

## Description

Parameter was missing.

## Related issues or tickets

https://github.com/docker/buildx/issues/3215#issuecomment-2931258854

## Reviews

<!-- Notes for reviewers here -->
<!-- List applicable reviews (optionally @tag reviewers) -->

- [ ] Technical review
- [ ] Editorial review
- [ ] Product review

_vale/config/vocabularies/Docker/accept.txt

@@ -4,25 +4,34 @@ Anchore
 Apple
 Artifactory
 Azure
+bootup
 Btrfs
 BuildKit
 BusyBox
 CentOS
 Ceph
+cgroup
 Chrome
 Chrome DevTools
 Citrix
 CloudFront
 Codefresh
 Codespaces
+config
+containerd
 Couchbase
 CouchDB
+datacenter
 Datadog
 Ddosify
 Debootstrap
+deprovisioning
+deserialization
+deserialize
 Dev
 Dev Environments?
 Dex
+displayName
 Django
 DMR
 Docker Build Cloud
@@ -37,14 +46,18 @@ Docker Team
 Docker-Sponsored Open Source
 Docker's
 Dockerfile
+dockerignore
 Dockerize
 Dockerizing
 Entra
-Ethernet
 EPERM
+Ethernet
 Fargate
 Fedora
+firewalld
 Flink
+fluentd
+g?libc
 GeoNetwork
 GGUF
 Git
@@ -52,9 +65,12 @@ GitHub( Actions)?
 Google
 Grafana
 Gravatar
+gRPC
 HyperKit
+inotify
 Intel
 Intune
+iptables
 IPv[46]
 IPvlan
 Jamf
@@ -64,48 +80,86 @@ JUnit
 Kerberos
 Kitematic
 Kubeadm
+kubectl
+kubefwd
+kubelet
 Kubernetes
 Laradock
 Laravel
+libseccomp
 Linux
 LinuxKit
 Logstash
+lookup
 Mac
+macOS
+macvlan
 Mail(chimp|gun)
+mfsymlinks
 Microsoft
+minikube
+monorepos?
+musl
 MySQL
+nameserver
+namespace
+namespacing
+netfilter
+netlabel
 Netplan
 NFSv\d
 Nginx
+npm
 Nutanix
 Nuxeo
 OAuth
 Okta
 Ollama
+osquery
+osxfs
 OTel
 Paketo
+pgAdmin
 PKG
 Postgres
 PowerShell
 Python
+rollback
+rootful
+runc
 Ryuk
 S3
 Slack
+snapshotters?
 Snyk
 Solr
 SonarQube
 SQLite
+stdin
+stdout
+subfolder
 Syft
+syntaxes
 Sysbox
+sysctls
 Sysdig
+systemd
 Testcontainers
+tmpfs
 Traefik
 Trixie
 Ubuntu
+ufw
+uid
+umask
 Unix
+unmanaged
 VMware
+vpnkit
+vSphere
 Wasm
 Windows
+windowsfilter
 WireMock
 Xdebug
 Zscaler
@@ -166,56 +220,4 @@ Zsh
 [Vv]irtiofs
 [Vv]irtualize
 [Ww]alkthrough
-bootup
-cgroup
-config
-containerd
-datacenter
-deprovisioning
-deserialization
-deserialize
-displayName
-dockerignore
-firewalld
-fluentd
-g?libc
-gRPC
-inotify
-iptables
-kubectl
-kubefwd
-kubelet
-libseccomp
-lookup
-macOS
-macvlan
-mfsymlinks
-minikube
-monorepos?
-musl
-nameserver
-namespace
-namespacing
-netfilter
-netlabel
-npm
-osquery
-osxfs
-pgAdmin
-rollback
-rootful
-runc
-snapshotters?
-stdin
-stdout
-syntaxes
-sysctls
-systemd
-tmpfs
-ufw
-uid
-umask
-unmanaged
-vSphere
-vpnkit
-windowsfilter
+

content/manuals/build/exporters/local-tar.md

@@ -25,9 +25,10 @@ $ docker buildx build --output type=tar[,parameters] .
 
 The following table describes the available parameters:
 
-| Parameter | Type   | Default | Description           |
-| --------- | ------ | ------- | --------------------- |
-| `dest`    | String |         | Path to copy files to |
+| Parameter        | Type    | Default | Description                                                                                                                                                                                                                            |
+|------------------|---------|---------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `dest`           | String  |         | Path to copy files to                                                                                                                                                                                                                  |
+| `platform-split` | Boolean | `true`  | When using the local exporter with a multi-platform build, by default, a subfolder matching each target platform is created in the destination directory. Set it to `false` to merge files from all platforms into the same directory. |
 
 ## Further reading