Better display of rule option default for array option

[bmish]

Before:

Name	Description	Type	Default
methods	An additional list of methods.	Array	``
methods2	An additional list of methods.	Array	hello world,1,2,3

After:

Name	Description	Type	Default
methods	An additional list of methods.	Array	[]
methods2	An additional list of methods.	Array	[hello world, 1, 2, 3]

Open to tweaking this further if there is a more standard or aesthetic format to use.

Part of: #491