New template instructions

_includes/templates/_errorthrower.md

@@ -0,0 +1,16 @@
+### ERROR: You must define a <span style="font-family: monospace">`{{ include.missing_block }}`</span> block
+{: style="color:red" }
+
+This template requires that you provide text that {{ include.purpose }}. The text in this block will
+be displayed under the heading **{{ include.heading }}**.
+
+To get rid of this message and take advantage of this template, define the `{{ include.missing_block }}`
+variable and populate it with content.
+
+```liquid
+{% raw %}{%{% endraw %} capture {{ include.missing_block }} {% raw %}%}{% endraw %}
+Text that {{ include.purpose }}.
+{% raw %}{%{% endraw %} endcapture {% raw %}%}{% endraw %}
+```
+
+<!-- TEMPLATE_ERROR -->