chore: mark generated openrpc and docs as generated (#13035)

misc: mark generated openrpc and docs as generated

So they are by default non-expanded in the diff

Signed-off-by: Jakub Sztandera <oss@kubuxu.com>

Author: Kubuxu

.gitattributes

@@ -1,2 +1,6 @@
 chain/actors/builtin/*/v* linguist-generated=true
 chain/actors/builtin/*/message* linguist-generated=true
+build/openrpc/** linguist-generated=true
+documentation/en/api-*.md linguist-generated=true
+documentation/en/cli-*.md linguist-generated=true
+