Use smaller symbols for \triangleleft and \triangleright

[DominikPeters]

The current unicode symbols used by LaTeXML for \triangleleft and \triangleright are larger than the symbols used when LaTeX is used. I propose changing the unicode symbols U+25C1 ◁ White Left-Pointing Triangle to U+25C3 ◃ White Left-Pointing Small Triangle, and similarly for right-pointing.

Example document:

\documentclass{article}
\begin{document}
    Test string: $x \bigtriangleup y \bigtriangledown z \triangleleft w \triangleright v$
\end{document}

PDF: LaTeXML: LaTeXML with this pull request: