Mix attributes from Operator Mono with Fira Code for ligatures

styles.less

atom-text-editor {
    /*font-family: "OperatorMono-Medium";*/
    font-family: "Fira Code";
    font-size: 18px;
    font-weight: normal;
    line-height: 1.7;
}

atom-panel.tool-panel {
    font-size: 0.88em;
}

.syntax--entity.syntax--other.syntax--attribute-name.syntax--js
{
    font-family: "OperatorMono-BookItalic";
    font-style: italic;
}

.editor .comment,
atom-text-editor.editor .syntax--comment {
    font-family: "OperatorMono-BookItalic";
    font-style: normal;
}