Add headers for each reference section (#256)

_sections/ref-table-english.md

@@ -10,10 +10,13 @@ It can be helpful to use a template to build an XLSForm rather than starting fro
 
 💡 Add the document to your templates in your spreadsheet software to make it easier to find. Don't forget to check back occasionally for updates!
 
-The reference tables from the template are available below for quick reference. You can use your browser's search feature to find what you're looking for.
+The types, appearances, and additional columns from the template are available below for quick reference. You can use your browser's search feature to find what you're looking for.
 
+### Types
 <iframe src="https://docs.google.com/spreadsheets/d/e/2PACX-1vSTaRWo-0HZ7gSLkSbmdEhYrHau-pOiGXeI02hCOQtdul4WvrEugbM7hnIr33fyLLywlUDRImZxyV63/pubhtml?gid=970638218&amp;single=true&amp;widget=true&amp;headers=false" width="100%" height="600px"></iframe>
 
+### Appearances
 <iframe src="https://docs.google.com/spreadsheets/d/e/2PACX-1vSTaRWo-0HZ7gSLkSbmdEhYrHau-pOiGXeI02hCOQtdul4WvrEugbM7hnIr33fyLLywlUDRImZxyV63/pubhtml?gid=750745522&amp;single=true&amp;widget=true&amp;headers=false" width="100%" height="600px"></iframe>
 
-<iframe src="https://docs.google.com/spreadsheets/d/e/2PACX-1vSTaRWo-0HZ7gSLkSbmdEhYrHau-pOiGXeI02hCOQtdul4WvrEugbM7hnIr33fyLLywlUDRImZxyV63/pubhtml?gid=136067855&amp;single=true&amp;widget=true&amp;headers=false" width="100%" height="600px"></iframe>
+### Additional columns
+<iframe src="https://docs.google.com/spreadsheets/d/e/2PACX-1vSTaRWo-0HZ7gSLkSbmdEhYrHau-pOiGXeI02hCOQtdul4WvrEugbM7hnIr33fyLLywlUDRImZxyV63/pubhtml?gid=136067855&amp;single=true&amp;widget=true&amp;headers=false" width="100%" height="600px"></iframe>