How to implement my own auto complementation? (intellisense/roslyn)

[Hidanio]

Hello guys! I am new with Roslyn and doing some experiments. I am trying to write extensions for VS (2022) with custom autocomplete functionality, but i have some problems. I wanna do 2 things:
If we have comment that started with @ //@ -> @fruits: (and trigger to step 2)
If we have comment //@fruits: -> @fruits:apple/cherry/banana
I tried different variants, but it doesnt work. Nothing is happened
I tried to debug it, but breakpoint does not hit and nothing happened. I tried different variants and i didn`t find any literature about intellisense...Can you help me and give some advices/guides and how to fix it? I found that CompletionProvider can help, but nothing :(

using System.Threading.Tasks;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.Options;
using Microsoft.CodeAnalysis.Text;
using Microsoft.CodeAnalysis.Completion;
using System.Composition;
using Microsoft.IO;

namespace Fruits_VS
{
  [ExportCompletionProvider(nameof(ColorCompletionProvider), LanguageNames.CSharp)]
  [Shared]
  public sealed class ColorCompletionProvider : CompletionProvider
  {
    public override async Task ProvideCompletionsAsync(CompletionContext context)
    {
	    string currentLine = await GetCurrentLineTextAsync(context).ConfigureAwait(false);
      int indexOfAt = currentLine.LastIndexOf('@');
      int indexOfColon = currentLine.LastIndexOf(':');

      switch (indexOfAt >= 0)
      {
	      case true when indexOfColon < 0:
		      context.AddItem(CompletionItem.Create("@fruits:"));
		      break;
	      case true when indexOfColon > indexOfAt:
	      {
		      if (currentLine.Contains("@fruits:"))
		      {
			      var fruits= new[] { "apple", "cherry", "banana" };
			      foreach (var fruit in fruits)
			      {
				      context.AddItem(CompletionItem.Create(fruit ));
			      }
		      }

		      break;
	      }
      }
    }

    private async Task<string> GetCurrentLineTextAsync(CompletionContext context)
    {
      var text = await context.Document.GetTextAsync().ConfigureAwait(false);
      var position = context.Position;
      var line = text.Lines.GetLineFromPosition(position);
      return text.ToString(line.Span);
    }

    public override bool ShouldTriggerCompletion(SourceText text, int caretPosition, CompletionTrigger trigger, OptionSet options)
    {
      switch (trigger.Kind)
      {
	      case CompletionTriggerKind.Invoke:
		      return true;
	      case CompletionTriggerKind.Insertion when caretPosition > 0:
	      {
		      var currentCharacter = text[caretPosition - 1];
		      var lineStart = text.Lines.GetLineFromPosition(caretPosition).Start;
		      var lineTextUpToCaret = text.GetSubText(TextSpan.FromBounds(lineStart, caretPosition)).ToString();

		      return (currentCharacter == '@' && (lineTextUpToCaret.StartsWith("//") || lineTextUpToCaret.StartsWith("/*")))
		             || (currentCharacter == ':' && lineTextUpToCaret.Contains('@') && (lineTextUpToCaret.StartsWith("//") || lineTextUpToCaret.StartsWith("/*")));
          }
	      default:
		      return false;
      }
    }
  }
}