fix(typeahead): specify any type for formatters argument

[jnizet]

The generated .d.ts file doesn't specify any as the type of the formatter argument (value) when it is defined as

inputFormatter: (value) => string;

Declaring it with an explicit any type fixes the issue:

inputFormatter: (value: any) => string;

That is quite strange, because for the attributes of NgbTypeaheadWindow which don't have a explicit type declared, like for example

@Input() results;

The corresponding attribute in the generated .d.ts file does have an explicit any type declared:

results: any;

So this looks like a bug or limitation of the typescript compiler.

[pkozlowski-opensource]

So this looks like a bug or limitation of the typescript compiler

Agreed, this looks fishy. Let's get this PR in as the change doesn't hurt.