cmd/golangorg: use 8 letters to form index split suffix

The default suffix length is 2 letters, which can cause split files to
have suffixes such as .cc, .go, and so on. Files with those suffixes
are misinterpreted to be source code files, and prevent the golangorg
command from building successfully.

Avoid this problem by using a suffix of length 8.

Use a single space to separate flags and values, for consistency.

Change-Id: I5120286a6f56091db8e46e6a74ca2eb98994de60
Reviewed-on: https://go-review.googlesource.com/c/website/+/220997
Reviewed-by: Alexander Rakoczy <alex@golang.org>
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

cmd/golangorg/generate-index.bash

@@ -57,7 +57,7 @@ makeIndexfile() {
 splitIndexfile() {
 	echo "*** split $INDEXFILE"
 	rm -f $SPLITFILES*
-	split -b8m $INDEXFILE $SPLITFILES
+	split -b 8m -a 8 $INDEXFILE $SPLITFILES
 }
 
 cd $(dirname $0)