Improve JsonField form template (#639)

Author: jowilf

starlette_admin/__init__.py

@@ -1,4 +1,4 @@
-__version__ = "0.15.0rc8"
+__version__ = "0.15.0rc9"
 
 from ._types import ExportType as ExportType
 from ._types import RequestAction as RequestAction

starlette_admin/templates/forms/json.html

@@ -5,6 +5,6 @@
 </div>
 <input type="text"
        name="{{ field.id }}"
-       value="{{ (data|tojson) if data else 'null' }}"
+       value="{{ (data|tojson|forceescape) if data else 'null' }}"
        hidden/>
 {% include "forms/_error.html" %}