FlintTextSpan constructor
Creates a styled span of text with optional link handling.
Example:
FlintTextSpan(
  "Click here",
  onTap: "https://flintdart.eulogia.net",
  style: TextStyle(color: "#007BFF", decoration: TextDecoration.underline),
)
Implementation
FlintTextSpan(this.text, {this.style, this.onTap});