[S32::IO] unconfuse description of &spurt, _edwin++

S32-setting-library/IO.pod

@@ -155,16 +155,15 @@ The routine will C<fail> if the file does not exist, or is a directory.
 
 Opens the file for writing, dumps the contents, and closes the file.
 
-This routine will C<fail> if the file exists, unless the C<:append> flag is
-set, in which case it will instead add the given contents at the end of the
-file.
+This routine will C<fail> if the file exists and the C<:createonly> is
+set.
+
+If C<:append> is provided, an existing file will not be clobbered, but the
+string will be appended.
 
 The routine will also C<fail> with the corresponding exception if there was any
 other error in opening, writing, or closing.
 
-If the C<:createonly> flag was passed, C<slurp> fails if the file already
-exists, and refuses to overwrite it.
-
 =item chdir
 
     multi sub chdir(Str:D)