createLanguageNode = (langName, langColor) => {
  return `
    <g data-testid="primary-lang">
      <circle data-testid="lang-color" cx="0" cy="-5" r="6" fill="${langColor}" />
      <text data-testid="lang-name" class="gray" x="15">${langName}</text>
    </g>
    `;
}
Creates a node to display the primary programming language of the repository/gist.

@param {string} langName Language name.
@param {string} langColor Language color.
@returns {string} Language display SVG object.