List data-filter type

[jeff-ph]

Would like an attribute such as data-filter-type that allows for different pattern matching with list items. Currently the filter only applies to list items containing the text entered, but what is often more useful is to match items that start with the text entered.

Attribute could accept 3 strings, such as:

start = Match list items starting with the text entered
contains = Match list items that contain the text entered (this is the current function)
end = Match list items ending with the text entered

[toddparker]

We'd like to make this configurable in a flexible way to people can write whatever search logic they want. Want to chime in with API ideas here:
#2006

[gseguin]

Closing as #2216 lets the developer handle that kind of filter through a callback.