StaticText oddities

[maximlt]

While having a look at #2663, I noticed a couple of things that could be fixed/clarified about the StaticText widget.

1. Issue with name parameter of some widgets #1294 already mentions it, if value is not given, the widget doesn't display name. It renders as an empty Div.
2. The docs say that the accepted type for value is a string, which is what one could expect given the widget's name. However it actually accepts any type (value = param.Parameter(default=None)), and uses the string representation of the object to display it. This can have some undesired consequences, such displaying Title: None for None or Title: for functions (and classes) as they're turned into <function ...></function> in the Div.
3. Updating value is as simple as st = StaticText(name='Name', value='Bob'); st.value = 'Bill'. But it's also possible to do it with st.value = '<b>Name</b>: John. This is not documented, it's tested however.

I think 1. should be fixed; it might be too late to fix 2. but there could more info in the docs; 3. should not really be supported although it's likely no one has ever used that or will ever do.