Fix a typo found by Eric D. Moyer, closes SF 807813.
Will backport to 2.3.
diff --git a/Doc/dist/dist.tex b/Doc/dist/dist.tex
index dd204be..87fc984 100644
--- a/Doc/dist/dist.tex
+++ b/Doc/dist/dist.tex
@@ -1477,7 +1477,7 @@
This function can be used to retrieve special folder locations on
Windows like the Start Menu or the Desktop. It returns the full path
-to the folder. 'csidl_string' must be on of the following strings:
+to the folder. 'csidl_string' must be one of the following strings:
\begin{verbatim}
"CSIDL_APPDATA"