Add hover for breakpoint widget placeholder

Because it can easily be cut off in a slightly narrow editor
Fix #221506

src/vs/workbench/contrib/debug/browser/breakpointWidget.ts

@@ -6,6 +6,7 @@
 import * as dom from 'vs/base/browser/dom';
 import { StandardKeyboardEvent } from 'vs/base/browser/keyboardEvent';
 import { Button } from 'vs/base/browser/ui/button/button';
+import { getDefaultHoverDelegate } from 'vs/base/browser/ui/hover/hoverDelegateFactory';
 import { ISelectOptionItem, SelectBox } from 'vs/base/browser/ui/selectBox/selectBox';
 import { CancellationToken } from 'vs/base/common/cancellation';
 import { onUnexpectedError } from 'vs/base/common/errors';
@@ -34,6 +35,7 @@ import * as nls from 'vs/nls';
 import { IConfigurationService } from 'vs/platform/configuration/common/configuration';
 import { IContextKeyService } from 'vs/platform/contextkey/common/contextkey';
 import { IContextViewService } from 'vs/platform/contextview/browser/contextView';
+import { IHoverService } from 'vs/platform/hover/browser/hover';
 import { IInstantiationService, createDecorator } from 'vs/platform/instantiation/common/instantiation';
 import { ServiceCollection } from 'vs/platform/instantiation/common/serviceCollection';
 import { IKeybindingService } from 'vs/platform/keybinding/common/keybinding';
@@ -109,6 +111,7 @@ export class BreakpointWidget extends ZoneWidget implements IPrivateBreakpointWi
 		@IKeybindingService private readonly keybindingService: IKeybindingService,
 		@ILabelService private readonly labelService: ILabelService,
 		@ITextModelService private readonly textModelService: ITextModelService,
+		@IHoverService private readonly hoverService: IHoverService
 	) {
 		super(editor, { showFrame: true, showArrow: false, frameWidth: 1, isAccessible: true });
 
@@ -221,6 +224,7 @@ export class BreakpointWidget extends ZoneWidget implements IPrivateBreakpointWi
 		this.createModesInput(container);
 
 		this.inputContainer = $('.inputContainer');
+		this.toDispose.push(this.hoverService.setupManagedHover(getDefaultHoverDelegate('mouse'), this.inputContainer, this.placeholder));
 		this.createBreakpointInput(dom.append(container, this.inputContainer));
 
 		this.input.getModel().setValue(this.getInputValue(this.breakpoint));