PRDOC: Document `validate: false` (#7117)

docs/contributor/prdoc.md

@@ -81,9 +81,6 @@ picked if no other applies. The `None` option is equivalent to the `R0-silent` l
 level. Experimental and private APIs are exempt from bumping and can be broken at any time. Please
 read the [Crate Section](../RELEASE.md) of the RELEASE doc about them.
 
-> **Note**: There is currently no CI in place to sanity check this information, but should be added
-> soon.
-
 ### Example
 
 For example when you modified two crates and record the changes:
@@ -106,3 +103,21 @@ you do not need to bump a crate that had a SemVer breaking change only from re-e
 crate with a breaking change.  
 `minor` an `patch` bumps do not need to be inherited, since `cargo` will automatically update them
 to the latest compatible version.
+
+### Overwrite CI check
+
+The `check-semver` CI check is doing sanity checks based on the provided `PRDoc` and the mentioned
+crate version bumps. The tooling is not perfect and it may recommends incorrect bumps of the version.
+The CI check can be forced to accept the provided version bump. This can be done like:
+
+```yaml
+crates:
+  - name: frame-example
+    bump: major
+    validate: false
+  - name: frame-example-pallet
+    bump: minor
+```
+
+By putting `validate: false` for `frame-example`, the version bump is ignored by the tooling. For
+`frame-example-pallet` the version bump is still validated by the CI check.