exec groups: remove outdated --experimental_* documentation.

PiperOrigin-RevId: 382526233

site/docs/exec-groups.md

diff --git a/site/docs/exec-groups.md b/site/docs/exec-groups.md
index aac6455..1cbec51 100644
--- a/site/docs/exec-groups.md
+++ b/site/docs/exec-groups.md
@@ -11,12 +11,6 @@
 performs its own [toolchain resolution](toolchains.md#toolchain-resolution).
 
 ## Current status
-To use Starlark rules that create execution groups, set
-`--experimental_exec_groups=true` on your command line or in a .bazelrc:
-
-```shell
-$ bazel build //target/with/exec/group --experimental_exec_groups
-```
 
 ## Background