Fixed wrong sentence in README.md

I was confused with the part of the sentence below the list of options and figured out it belonged to the third bullet point. At least now it makes sense to me. If I'm wrong, please think about rewriting this section because it confused me. If you explain it to me I'm more than happy to rephrase it!

Author: Sgoettschkes

Diff for: README.md

@@ -47,11 +47,9 @@ The type adds four options to the collection type options, of which one is requi
 
   * `value_type` (required) defines which form type to use to render the value field
   * `value_options` optional options to the child defined in `value_type`
-  * `allowed_keys` if this option is provided, the key field (which is usually a simple text field) will change
+  * `allowed_keys` if this option is provided, the key field (which is usually a simple text field) will change to a `choice` field, and allow only those values you supplied in the this option.
   * `use_container_object` see explanation below at 'The KeyValueCollection'
 
-to a `choice` field, and allow only those values you supplied in the this option.
-
 Besides that, this type overrides some defaults of the collection type and it's recommended you don't change them:
 `type` is set to `burgov_key_value_row` and `allow_add` and `allow_delete` are always `true`.