[DOCS] Fix typo in URL-based access control docs (#61896) (#61985)

Co-authored-by: George Tseres <george.tseres@gmail.com>

docs/reference/api-conventions.asciidoc

@@ -678,4 +678,4 @@ URL, set `rest.action.multi.allow_explicit_index` to `false` in `elasticsearch.y
 
 
 This causes  {es} to
-reject requests that explicitly specfiy a data stream or index in the request body.
+reject requests that explicitly specify a data stream or index in the request body.