Remove trailing whitespace.
diff --git a/Doc/distutils/configfile.rst b/Doc/distutils/configfile.rst
index 0ccd5fd..890047c 100644
--- a/Doc/distutils/configfile.rst
+++ b/Doc/distutils/configfile.rst
@@ -63,7 +63,7 @@
      --include-dirs (-I)  list of directories to search for header files
      --define (-D)        C preprocessor macros to define
      --undef (-U)         C preprocessor macros to undefine
-     --swig-opts          list of SWIG command line options        
+     --swig-opts          list of SWIG command line options
    [...]
 
 Note that an option spelled :option:`--foo-bar` on the command-line  is spelled