SF #801306: Bad RE in scanf example

Doc/lib/libre.tex

@@ -867,7 +867,7 @@ offers some more-or-less equivalent mappings between
   \lineii{\code{\%d}}
          {\regexp{[-+]?\e d+}}
   \lineii{\code{\%e}, \code{\%E}, \code{\%f}, \code{\%g}}
-         {\regexp{[-+]?(\e d+(\e.\e d*)?|\e d*\e.\e d+)([eE]\e d+)?}}
+         {\regexp{[-+]?(\e d+(\e.\e d*)?|\e d*\e.\e d+)([eE][-+]?\e d+)?}}
   \lineii{\code{\%i}}
          {\regexp{[-+]?(0[xX][\e dA-Fa-f]+|0[0-7]*|\e d+)}}
   \lineii{\code{\%o}}