[LRN] Change \triangle and \ddots character bindings

\triangle is now a bigger triangle
\ddots now points down and right

src/commands/math/advancedSymbols.js

diff --git a/src/commands/math/advancedSymbols.js b/src/commands/math/advancedSymbols.js
index 77929fa..0ed2846 100644
--- a/src/commands/math/advancedSymbols.js
+++ b/src/commands/math/advancedSymbols.js
@@ -180,7 +180,7 @@
 LatexCmds.vdots = bind(VanillaSymbol, '\\vdots ', '⋮');
 LatexCmds.ddots = bind(VanillaSymbol, '\\ddots ', '⋱');
 LatexCmds.surd = bind(VanillaSymbol, '\\surd ', '√');
-LatexCmds.triangle = bind(VanillaSymbol, '\\triangle ', '▵');
+LatexCmds.triangle = bind(VanillaSymbol, '\\triangle ', '△');
 LatexCmds.ell = bind(VanillaSymbol, '\\ell ', 'ℓ');
 LatexCmds.top = bind(VanillaSymbol, '\\top ', '⊤');
 LatexCmds.flat = bind(VanillaSymbol, '\\flat ', '♭');