Fix \not and \neq on Chrome via new Unicode symbol U+E020 (#1852)

* Fix \not and \neq via new Unicode symbol U+E020

Fix #1842

* Fix font metrics

* Update screenshots

* Use lower case letters in code points

src/symbols.js

@@ -568,7 +568,7 @@ defineSymbol(math, main, rel, "\u2265", "\\geq", true);
 defineSymbol(math, main, rel, "\u2190", "\\gets");
 defineSymbol(math, main, rel, ">", "\\gt");
 defineSymbol(math, main, rel, "\u2208", "\\in", true);
-defineSymbol(math, main, rel, "\u0338", "\\@not");
+defineSymbol(math, main, rel, "\ue020", "\\@not");
 defineSymbol(math, main, rel, "\u2282", "\\subset", true);
 defineSymbol(math, main, rel, "\u2283", "\\supset", true);
 defineSymbol(math, main, rel, "\u2286", "\\subseteq", true);