fix(json): default should be an escaped json string (#308)

Author: Tieske

convention.md

@@ -368,7 +368,7 @@ the formats for displaying values.
 | enum         | yes      |          | A comma-separated list of non-quoted values. Eg. `value1,value2,value3`. Leading- and trailing whitespace is significant. Individual values can not be an empty string, hence at least 1 value must be specified in the format. Duplicates are not allowed. |
 | color        | yes      |          | A comma-separated list of color formats supported; `rgb`, `hsv`, and/or `xyz`. The formats should be listed in order of preference (most preferred first, least preferred last). See the [color type](#color) for the resulting value formats. E.g. a device supporting RGB and HSV, where RGB is preferred, would have its format set to `"rgb,hsv"`. |
 | boolean      | no       | `false,true` | Identical to an enum with 2 entries. The first represents the `false` value and the second is the `true` value. Eg. `close,open` or `off,on`. If provided, then both entries must be specified. **Important**:  the format does NOT specify valid payloads, they are descriptions of the valid payloads `false` and `true`. |
-| json         | no       | `{"anyOf": [{"type": "array"},{"type": "object"}]}` | A [JSONschema](http://json-schema.org/) definition, which is added as a string (escaped), NOT as a nested json-object. See [JSON considerations](#json-considerations), for some ideas wrt compatibility. If a client fails to parse/compile the JSONschema, then it should ignore the given schema and fall back to the default schema.
+| json         | no       | `{\"anyOf\": [{\"type\": \"array\"},{\"type\": \"object\"}]}` | A [JSONschema](http://json-schema.org/) definition, which is added as a string (escaped), NOT as a nested json-object. See [JSON considerations](#json-considerations), for some ideas wrt compatibility. If a client fails to parse/compile the JSONschema, then it should ignore the given schema and fall back to the default schema.
 
 
 #### Units