Implement $...$ within \text via styling node (#637)

test/screenshotter/ss_data.yaml

@@ -170,6 +170,7 @@ Symbols1: |
     \maltese\degree\pounds\$
     \text{\maltese\degree\pounds\textdollar}
 Text: \frac{a}{b}\text{c~ {ab} \ e}+fg
+TextWithMath: \text{for $a < b$ and $ c < d $}.
 Unicode: \begin{matrix}\text{ÀàÇçÉéÏïÖöÛû} \\ \text{БГДЖЗЙЛФЦШЫЮЯ} \\ \text{여보세요} \\ \text{私はバナナです} \end{matrix}
 UnsupportedCmds:
     tex: \err\,\frac\fracerr3\,2^\superr_\suberr\,\sqrt\sqrterr