templates: Use heredoc in pre-commit hook

This way, it is easier to see how the text we give the end users
would look like, and it will allow us to use (near) full width
of the source file.

Signed-off-by: Richard Hartmann <richih.mailinglist@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: RichiH

templates/hooks--pre-commit.sample

@@ -31,18 +31,19 @@ if [ "$allownonascii" != "true" ] &&
 	test $(git diff --cached --name-only --diff-filter=A -z $against |
 	  LC_ALL=C tr -d '[ -~]\0' | wc -c) != 0
 then
-	echo "Error: Attempt to add a non-ascii file name."
-	echo
-	echo "This can cause problems if you want to work"
-	echo "with people on other platforms."
-	echo
-	echo "To be portable it is advisable to rename the file ..."
-	echo
-	echo "If you know what you are doing you can disable this"
-	echo "check using:"
-	echo
-	echo "  git config hooks.allownonascii true"
-	echo
+	cat <<\EOF
+Error: Attempt to add a non-ascii file name.
+
+This can cause problems if you want to work
+with people on other platforms.
+
+To be portable it is advisable to rename the file.
+
+If you know what you are doing you can disable this
+check using:
+
+  git config hooks.allownonascii true
+EOF
 	exit 1
 fi