The fallback image for the MathML mode is in SVG format, except for Internet
Explorer < 9 for which PNG is used instead. This commit makes the label of the
MathML mode sligthly more accurate, by mentioning that PNG may be used.
Change-Id: I77c8a8dcb7d2f111f029e1cd5b6f3442640be57e
This is a subjective comment that was not true for everybody (trade-off
between speed & quality). Moreover, this is now an orthogonal option to enable
MathJax client-side rather than a separate rendering mode per se, so it is
confusing to compare it against the other modes. The "recommended" mode in the
future is likely to become MathML + SVG fallback (which instead uses MathJax
server-side) ; but it's probably best to keep neutral regarding the user's
preferences.
Change-Id: I5c6ff7c95cded4f06f6bfdef43dbe190e42a2968
