Use packaged copy of MathJax from libjs-mathjax

Use packaged copy of MathJax from libjs-mathjax

Origin: vendor
Forwarded: not-needed
Last-Update: 2020-11-24

FontForge documentation uses sphinx.ext.mathjax which insert script links
to MathJax served on remote CDNs.

This patch, together with debian/fontforge-doc.links, replaces remote
scripts with MathJax from the libjs-mathjax package.
See https://bugs.debian.org/739300 for discussion.

Fixes Lintian privacy-breach-generic warnings.
Last-Update: 2020-11-24
Gbp-Pq: Name 0003-use-local-libjs-mathjax.patch