RemoveEmptyTags added to query.html.markdown

website/source/docs/agent/http/query.html.markdown

@@ -177,7 +177,8 @@ to static templates, except with some additional fields and features. Here's an
   "Name": "geo-db",
   "Template": {
     "Type": "name_prefix_match",
-    "Regexp": "^geo-db-(.*?)-([^\\-]+?)$"
+    "Regexp": "^geo-db-(.*?)-([^\\-]+?)$",
+    "RemoveEmptyTags": false
   },
   "Service": {
     "Service": "mysql-${match(1)}",
@@ -192,7 +193,7 @@ to static templates, except with some additional fields and features. Here's an
 ```
 
 The new `Template` structure configures a prepared query as a template instead of a
-static query. It has two fields:
+static query. It has three fields:
 
 `Type` is the query type, which must be "name_prefix_match". This means that the
 template will apply to any query lookup with a name whose prefix matches the `Name`
@@ -207,6 +208,10 @@ takes the first item after the "-" as the database name and everything else afte
 a tag. See the [RE2](https://github.com/google/re2/wiki/Syntax) reference for syntax
 of this regular expression.
 
+An optional `RemoveEmptyTags` boolean may be set to true, if the returned tags list
+is to be stripped of empty string elements. `RemoveEmptyTags` defaults to false
+(all tags are being returned, including empty strings).
+
 All other fields of the query have the same meanings as for a static query, except
 that several interpolation variables are available to dynamically populate the query
 before it is executed. All of the string fields inside the `Service` structure are
@@ -470,7 +475,8 @@ a JSON body will be returned like this:
     "Name": "geo-db",
     "Template": {
       "Type": "name_prefix_match",
-      "Regexp": "^geo-db-(.*?)-([^\\-]+?)$"
+      "Regexp": "^geo-db-(.*?)-([^\\-]+?)$",
+      "RemoveEmptyTags": false
     },
     "Service": {
       "Service": "mysql-customer",