examples: consistently omit extension for scripts

examples/notify-email-text-log

@@ -0,0 +1,18 @@
+#!/bin/bash -e
+
+# IMPORTANT: change these to appropriate values, or fetch them, for example
+# from the environment or from $(git show -s --format='%ae' $rev)
+TO_EMAIL=engineering@example.com
+FROM_EMAIL=laminar@example.com
+
+LAMINAR_URL=${LAMINAR_BASE_URL:-http://localhost:8080}
+
+sendmail -t <<EOF
+From: $FROM_EMAIL
+To: $TO_EMAIL
+Subject: $JOB #$RUN: $RESULT
+Mime-Version: 1.0
+Content-Type: text/plain; charset=utf-8
+
+$(curl -s $LAMINAR_URL/log/$JOB/$RUN)
+EOF