feat: remove fields scheduled to be removed in 4.0 (#1439)

BREAKING CHANGE:
Popover:
'nbPopoverMode' input removed. Use 'nbPopoverTrigger' instead.
NbPopoverDirective 'mode' property removed. Use 'trigger' instead.

NbSelectComponent 'selectionChange' removed. Use nb-select (selected)
binding to track selection change and <nb-option (click)=""> to track
option click.

src/framework/theme/components/popover/popover.directive.ts

@@ -143,21 +143,6 @@ export class NbPopoverDirective implements NbDynamicOverlayController, OnChanges
   @Input('nbPopoverAdjustment')
   adjustment: NbAdjustment = NbAdjustment.CLOCKWISE;
 
-  /**
-   * Deprecated, use `trigger`
-   * @deprecated
-   * @breaking-change 4.0.0
-   * */
-  @Input('nbPopoverMode')
-  set mode(mode) {
-    console.warn(`Popover 'nbPopoverMode' input is deprecated and will be removed as of 4.0.0.
-      Use 'nbPopoverTrigger' instead.`);
-    this.trigger = mode;
-  }
-  get mode() {
-    return this.trigger;
-  }
-
   /**
    * Describes when the container will be shown.
    * Available options: `click`, `hover`, `hint`, `focus` and `noop`

src/framework/theme/components/select/select.component.ts

@@ -25,7 +25,7 @@ import {
   ViewChild,
 } from '@angular/core';
 import { ControlValueAccessor, NG_VALUE_ACCESSOR } from '@angular/forms';
-import { merge, Observable, Subject } from 'rxjs';
+import { merge } from 'rxjs';
 import { startWith, switchMap, takeWhile, filter } from 'rxjs/operators';
 
 import {
@@ -551,15 +551,6 @@ export class NbSelectComponent<T> implements AfterViewInit, AfterContentInit, On
    */
   overlayPosition: NbPosition = '' as NbPosition;
 
-  protected selectionChange$: Subject<NbOptionComponent<T>> = new Subject();
-  /**
-   * Stream of events that will fire when one of the options is clicked.
-   * @deprecated
-   * Use nb-select (selected) binding to track selection change and <nb-option (click)=""> to track option click.
-   * @breaking-change 4.0.0
-   **/
-  readonly selectionChange: Observable<NbOptionComponent<T>> = this.selectionChange$.asObservable();
-
   protected ref: NbOverlayRef;
 
   protected triggerStrategy: NbTriggerStrategy;
@@ -858,10 +849,7 @@ export class NbSelectComponent<T> implements AfterViewInit, AfterContentInit, On
         }),
         takeWhile(() => this.alive),
       )
-      .subscribe((clickedOption: NbOptionComponent<T>) => {
-        this.handleOptionClick(clickedOption);
-        this.selectionChange$.next(clickedOption);
-      });
+      .subscribe((clickedOption: NbOptionComponent<T>) => this.handleOptionClick(clickedOption));
   }
 
   protected subscribeOnOverlayKeys(): void {