Improve examples when creating a Dynamic Table Config

[JavierArredondo]

When you create a Dynamic Tag, the documentation shows examples using variables such as $table, $dataset and $project.

The following examples exist:

• select count(*) from $table;
• select count(distinct(account_id)) from $table;
• select count(*) > 1 from $table where account_id is null;
• select rating from dw-project.quality.scores where table =`$table' and dataset = `$dataset` and project = `$project`;
• select '30-DAYS';

As you can see, some examples use $table and another uses `$table`, but only the `$table` cases work.

datacatalog-tag-engine/templates/dynamic_table_config.html

Lines 19 to 38 in ee92750

	<h5 style="width: 800px;">To include a field in your tag, click on the checkbox next to the field and enter a query expression in the text box. <br>
	<br>
	The query expression must be a <i>valid</i> select statement in BigQuery. It may contain filter, aggregate functions, joins, groupings, subqueries, etc. as long as it's a valid select statement.<br>
	<br>
	The query expression may reference these variables:<br>
	- <b>$table</b> refers to the BQ table (or view) being tagged<br>
	- <b>$dataset</b> refers to the BQ dataset of the table (or view) being tagged<br>
	- <b>$project</b> refers to the BQ project of the table (or view) being tagged<br>
	<br>
	Here are some examples: <br>
	&nbsp;select count(*) from $table;<br>
	&nbsp;select count(distinct(account_id)) from $table;<br>
	&nbsp;select count(*) > 1 from $table where account_id is null;<br>
	&nbsp;select rating from dw-project.quality.scores where table = '$table' and dataset = '$dataset' and project = '$project';<br>
	&nbsp;select '30-DAYS';<br>
	<br>
	Note: The result of the query expression must satisfy the type requirements of the field in the tag template. <br>
	For example, if the tag template field is of type string, the query expression must return a string type.