Reviewed by John Sullivan.

        Add more spelling/grammar related methods
        https://bugs.webkit.org/show_bug.cgi?id=51886

        * UIProcess/API/mac/WKView.mm:
        (-[WKView validateUserInterfaceItem:]):
        Handle more selectors.

        (-[WKView showGuessPanel:]):
        Add stub.

        (-[WKView checkSpelling:]):
        Ditto.

        (-[WKView toggleAutomaticSpellingCorrection:]):
        Toggle automatic spelling correction.

        * UIProcess/TextChecker.h:
        Add setAutomaticSpellingCorrectionEnabled and isAutomaticSpellingCorrectionEnabled.

        * UIProcess/mac/TextCheckerMac.mm:
        (WebKit::TextChecker::setAutomaticSpellingCorrectionEnabled):
        (WebKit::TextChecker::isAutomaticSpellingCorrectionEnabled):
        Update the toggle.

        * WebProcess/WebCoreSupport/WebPlatformStrategies.cpp:
        * WebProcess/WebCoreSupport/mac/WebErrorsMac.mm:
        Add a Radar URL for the localization FIXMEs.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@74989 268f45cc-cd09-0410-ab3c-d52691b4dbfc