An -> a

Thanks to Théo de Oliveira Santos
https://stacks.math.columbia.edu/tag/021Z#comment-4724

Author: aisejohan

topologies.tex

@@ -1335,7 +1335,7 @@ \section{The smooth topology}
 
 \begin{definition}
 \label{definition-smooth-covering}
-Let $T$ be a scheme. An {\it smooth covering of $T$} is a family
+Let $T$ be a scheme. A {\it smooth covering of $T$} is a family
 of morphisms $\{f_i : T_i \to T\}_{i \in I}$ of schemes
 such that each $f_i$ is smooth and such
 that $T = \bigcup f_i(T_i)$.