message: Fix <C-t> in insert mode
  Fixes
diff: @@ -204,12 +204,12 @@ class CommandInsertIndentInCurrentLine extends BaseCommand {
  const originalText = vimState.document.lineAt(position).text;
  const indentationWidth = TextEditor.getIndentationLevel(originalText);
  const tabSize = configuration.tabstop || Number(vimState.editor.options.tabSize);
  - const newIndentationWidth = (indentationWidth / tabSize + 1) * tabSize;
  + const newIndentationWidth = (Math.floor(indentationWidth / tabSize) + 1) * tabSize;
  vimState.recordedState.transformer.addTransformation({
  type: 'replaceText',
  - text: TextEditor.setIndentationLevel(originalText, newIndentationWidth),
  - range: new Range(position.getLineBegin(), position.getLineEnd()),
  + text: TextEditor.setIndentationLevel(originalText, newIndentationWidth).match(/^(\s*)/)![1],
  + range: new Range(position.getLineBegin(), position.with({ character: indentationWidth })),
  diff: new PositionDiff({ character: newIndentationWidth - indentationWidth }),
  });
  }
  