feat: Hide spelling issues while typing.

[Jason3S]

Because of the custom decorators in v4, it is possible to control when issues are displayed.

v4 comes with a command to show/hide issues. This is different than the enable/disable command. That command turns the spell checker on/off, almost like shutting it down and restarting it.

Added a couple of settings:

export interface SpellCheckerBehaviorSettings {
    /**
     * Control how spelling issues are displayed while typing.
     * See: `#cSpell.revealIssuesAfterMS#` to control when issues are revealed.
     * @title Hide Issues While Typing
     * @scope machine
     * @since 4.0.0
     * @default "Word"
     * @enumDescriptions [
     *  "Show issues while typing",
     *  "Hide issues in the current word",
     *  "Hide issues on the line",
     *  "Hide all issues in the document"]
     */
    hideIssuesWhileTyping?: 'Off' | 'Word' | 'Line' | 'Document';

    /**
     * Reveal hidden issues related to `#cSpell.hideIssuesWhileTyping#` after a delay in milliseconds.
     * @title Reveal Issues After a Delay in Milliseconds
     * @scope machine
     * @since 4.0.0
     * @default 1500
     * @enumDescriptions [
     *  "Show issues while typing",
     *  "Hide issues in the current word",
     *  "Hide issues on the line",
     *  "Hide all issues in the document"]
     */
    revealIssuesAfterDelayMS?: number;
}