Clean up internal/external split in platform docs.

PiperOrigin-RevId: 296002457
diff --git a/site/docs/platforms.md b/site/docs/platforms.md
index 67b197b..fe3ea64 100644
--- a/site/docs/platforms.md
+++ b/site/docs/platforms.md
@@ -98,6 +98,7 @@
 Note that it is an error for a platform to specify more than one value of the
 same constraint setting, such as `@platforms//cpu:x86_64` and
 `@platforms//cpu:arm` for `@platforms//cpu:cpu`.
+-->
 
 
 ## Generally useful constraints and platforms