Fix appendix section titles

The example style file has appendix titles formatted as "Appendix A.", but the current `.sty` file only outputs "A." by default. This can't be fixed by packages like `appendix` or `titlesec` due to the custom sectioning of the `.sty` file. This patch modifies the section display when the `\appendix` command is run so that the appendix titles are displayed correctly.

jmlr2e.sty

@@ -21,6 +21,8 @@
 % Do not define proof environemtn if already defined. (Thank you James Martens)
 % Last edited Sept 5, 2022 Alp Kucukelbir
 % Disclose funding.
+% Last edited Oct 17, 2022 Daniel LeJeune
+% Fixed appendix title display.
 %
 % The name of this file should follow the article document
 % type, e.g. \documentstyle[jmlr]{article}
@@ -131,6 +133,31 @@
  #7}}\fi
  \@xsect{#5}}
 
+% Title each appendix with `Appendix` before its letter
+\let\originalJMLRappendix\appendix
+\renewcommand{\appendix}{
+\originalJMLRappendix 
+\def\@sict##1##2##3##4##5##6[##7]##8{\ifnum ##2>\c@secnumdepth
+ \def\@svsec{}\else
+ \refstepcounter{##1}\edef\@svsec{\csname the##1\endcsname}\fi
+ \@tempskipa ##5\relax
+ \ifdim \@tempskipa>\z@
+ \begingroup ##6\relax
+ \@hangfrom{\hskip ##3\relax Appendix \@svsec.\hskip 0.1em}
+ {\interlinepenalty \@M ##8\par}
+ \endgroup
+ \csname ##1mark\endcsname{##7}\addcontentsline
+ {toc}{##1}{\ifnum ##2>\c@secnumdepth \else
+ \protect\numberline{\csname the##1\endcsname}\fi
+ ##7}\else
+ \def\@svsechd{##6\hskip ##3\@svsec ##8\csname ##1mark\endcsname
+ {##7}\addcontentsline
+ {toc}{##1}{\ifnum ##2>\c@secnumdepth \else
+ \protect\numberline{\csname the##1\endcsname}\fi
+ ##7}}\fi
+ \@xsect{##5}}
+}
+
 \def\@sect#1#2#3#4#5#6[#7]#8{\ifnum #2>\c@secnumdepth
  \def\@svsec{}\else 
  \refstepcounter{#1}\edef\@svsec{\csname the#1\endcsname\hskip 0.5em }\fi
@@ -348,16 +375,6 @@ are provided at \url{https://jmlr.org/papers/v#1/#6.html}.\hfill}}%
 % Research Note
 \long\def\researchnote#1{\noindent {\LARGE\it Research Note} #1}
 
-% \renewcommand{\appendix}{\par
-% \setcounter{section}{0}
-% \setcounter{subsection}{0}
-% \def\thesection{\Alph{section}}%
-% \ifdefined\theHsection \def\theHsection{\Alph{section}} \fi%
-% \def\section{\@ifnextchar*{\@startsiction{section}{1}{\z@}{-0.24in}{0.10in}%
-% {\large\bf\raggedright}}%
-% {\@startsiction{section}{1}{\z@}{-0.24in}{0.10in}
-% {\large\bf\raggedright Appendix\ }}}}
-
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 % PROOF, THEOREM, and FRIENDS
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

sample.tex

@@ -83,7 +83,7 @@ \section{Introduction}
 \newpage
 
 \appendix
-\section*{Appendix A.}
+\section{}
 \label{app:theorem}
 
 % Note: in this sample, the section number is hard-coded in. Following