clean up markup for --executable description

Doc/dist/dist.tex

@@ -641,8 +641,9 @@ anything very complicated.  The only clever feature is that if the
 first line of the script starts with \code{\#!} and contains the word
 ``python'', the Distutils will adjust the first line to refer to the
 current interpreter location. By default, it is replaced with the
-current interpreter location.  The '--executable=/-e' switch will
-allow the interpreter path to be explicitly overridden.
+current interpreter location.  The \longprogramopt{executable} (or
+\programopt{-e}) option will allow the interpreter path to be
+explicitly overridden.
 
 The \option{scripts} option simply is a list of files to be handled
 in this way.  From the PyXML setup script: