Allow to `apply` for all occurrences of the text

[kadishmal]

At the moment I have the following code which applies a certain style to the source text.

    SpanBuilder(source).apply(
      TextSpan(
        text: searchString,
        style: TextStyle(fontWeight: FontWeight.bold),
      ),
    );

The above code applies the style only on the first match, while I need to apply on all matches till the end of the source text.