Delete mathjax extension, remove img width 100%

[ezyang]

This is in preparation for turning on imgmath as a replacement
for KaTeX; we must not have width: 100% on images as it causes
rendering problems for img math.

Signed-off-by: Edward Z. Yang ezyang@fb.com

[soumith]

I'd merge it but CI is failing

[patmellon]

@ezyang Instead of removing width: 100% from _article.scss, I recommend that you add the following code to _sphinx_base.scss (beginning at line 777):

article.pytorch-article {
  .math {
    color: $not_quite_black;
    img {
      width: auto;
    }
  }
}

I'm just adding img { width: auto; } to the existing math class. This change should leave the tutorial images unaffected but ensure that the math images have the right size. Please let me know if this change works with the new math images.

[ezyang]

@Pat878 This CSS was not quite sufficient, I also had to handle inline math elements correctly.