remove an umlaut to avoid trouble with pythons in the wrong locale

vmodtool python running in the wrong locale may complain about an
invalid character

src/vmod_blobcode.vcc

@@ -424,7 +424,7 @@ AUTHORS
 UPLEX Nils Goroll Systemoptimierung
 
 This VMOD was originally adapted from, and is heavily indebted to, the
-digest VMOD by Kristian Lyngstøl.
+digest VMOD by Kristian Lyngstoel.
 
 HISTORY
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