I have several documents that I am looking to reduce redundant whitespace in and am looking to redefine align to include SwapAboveDisplaySkip from mathtools by default. Since I want to use it almost everywhere, I'd rather not have to manually include it everywhere.
Currently I have the following, which does what I want, except for a new environment rather than for align, which is essentially just the solution from here: Define a custom align, and align* environment
\documentclass{article}
\usepackage{amsmath, mathtools}
\makeatletter
\newenvironment{salign}
{\par\align \SwapAboveDisplaySkip}
{\endalign}
\newenvironment{salign*}
{\par
\start@align\@ne\st@rredtrue\m@ne}
{\endalign}
\makeatother
\begin{document}
\section{Foo}
\begin{salign}
a^2+b^2 & = c^2
\end{salign}
\end{document}
I don't want to use this as then I need to define additional files so that the syntax highlighting for my editor works, which means the code won't be portable.
Replacing with renewenvironment creates a recursive loop, I've also tried \let\oldalign\align
to fix this, but this doesn't compile.
\abovedisplayskip=\abovesdisplayshortskip
so that you always get the smaller spacing