It seems there is simply a missing space in the nullable formatting. I imagine it's supposed to be `number(double) | null`? Probably a simple fix to [here](https://github.com/Neoteroi/essentials-openapi/blob/4ffc7b1921835a22a386494c0acb4f4390f5f1a4/openapidocs/mk/v3/views_mkdocs/partial/schema-repr.html#L23) and [here](https://github.com/Neoteroi/essentials-openapi/blob/4ffc7b1921835a22a386494c0acb4f4390f5f1a4/openapidocs/mk/v3/views_markdown/partial/schema-repr.html#L23)? 
