FileIntelliHints is a concrete implementation of
com.jidesoft.hints.IntelliHints .
It allows user to type in a file patch quickly by providing them the hints based on what
is existed on file system.
IntelliHints is an interface that defines all necessary methods to implement
showing a hint popup depending on a context and allows user to pick from a list of hints.
IntelliHints.createHintsComponent() will create a component that contains the hints.