LaTeX reader/writer: change handling of math environments.

Certain environments in LaTeX will trigger math mode and can't
occur within math mode: e.g., `align` or `equation`.  Previously
we "downshifted" these, parsing an `align` environment as a
Math element with `aligned`, and an `equation` environment as a
regular display math element.  With this shift, we put these in
Math inlines but retain the original environments.

This works because:

1) texmath handles these environments just fine,
2) and so does MathJax;
3) when writing LaTeX we detect these environments in Math elements
   and emit them verbatim instead of putting them in `$..$` or
   `$$..$$`.

Closes #9711. Closes #9296.

1 files changed, 5 insertions, 1 deletions

diff --git a/test/command/10160.md b/test/command/10160.md
index fa3e97cd5..52e512b5a 100644
--- a/test/command/10160.md
+++ b/test/command/10160.md
@@ -7,5 +7,9 @@
 \begin{table}[h]
 \end{table}
 ^D
-[ Para [ Math DisplayMath "[0,1)" ] ]
+[ Para
+    [ Math
+        DisplayMath "\\begin{equation}\n  [0,1)\n\\end{equation}"
+    ]
+]
 ```