Merge pull request #921 from Octachron/latex_math_fix

latex math: remove line at the end of equation* environment

It is generally a good idea to avoid spurious blank line before the end of the equation* environment.
For example:

    \begin{equation*}
        \f\hat\xi\,e^{2 \pi i \xi x}
        \,d\xi
        
    \end{equation*}

In my tests, this blank line breaks at least the amsmath version of equation*.
This commit fix this issue that trimming the last part of the raw equation text before cutting a newline to end the equation* environment.

Author: Julow

src/latex/raw.ml

@@ -217,6 +217,9 @@ let equation ppf x =
   let name = "equation*" in
   mbegin ppf name;
   Fmt.cut ppf ();
+  (* A blank line before \end{equation*} is a latex error,
+     we trim on the right the user input to avoid any surprise *)
+  let x = Astring.String.drop ~rev:true ~sat:Astring.Char.Ascii.is_white x in
   Fmt.string ppf x;
   Fmt.cut ppf ();
   mend ppf name

test/generators/latex/Markup.tex

@@ -91,7 +91,6 @@ \subsection{Math\label{math}}%
     \f\relax{x} = \int_{-\infty}^\infty
     \f\hat\xi\,e^{2 \pi i \xi x}
     \,d\xi
-    
 \end{equation*}
 
 \subsection{Modules\label{modules}}%