feat(dropdown): add case sensitivity setting for search

[aexvir]

Description

ignoreCase was only used for affecting the label creation. This MR makes the filtering respect that setting, for both searches, on text and value.

Instead or reusing the same variable, as that would introduce a breaking change where none of the current users will have case insensitive search, this MR adds a new setting that allows setting the case sensitivity for the item filtering

Testcase

before: https://jsfiddle.net/3we8nb7j/
after: https://jsfiddle.net/ye1hg6c4/

Closes

#932

[lubber-de]

Your code works, but as ignoreCase is false by default, no existing application search dropdowns will work anymore without refactoring them by adding ignoreCase:true. (see your own jsfiddle example)
Although 2.8.0 allows breaking changes, this kind of change would be a bit too unexpected and i believe dropdowns are used a lot everywhere.
My suggestion is to make this an additional setting ignoreSearchCase (default true) , so ignoreCase will only work for the labels as before
@hammy2899 @exoego @prudho @ColinFrick Your opinions? (before @aexvir is going to change it)

[y0hami]

I agree with @lubber-de, keeping ignoreCase as backwards compatible is the way to go because changing its behavior can't be justified for the impact it would have on users. Also adding this setting allows the user more control over the search case.

[aexvir]

Yep, totally agree

[lubber-de]

LGTM

[exoego]

LGTM

[ColinFrick]

LGTM

[y0hami]

LGTM

[lubber-de]

Docs added by fomantic/Fomantic-UI-Docs#161

[y0hami]

@all-contributors please add @aexvir for code

[allcontributors]

@hammy2899

I've put up a pull request to add @aexvir! 🎉