[APM Tracing: Go] Update DD_TAGS documentation (#27132)

Author: mtoffl01

content/en/tracing/trace_collection/library_config/go.md

@@ -158,8 +158,8 @@ A JSON array of objects. Each object must have a `"sample_rate"`. The `"name"`,`
   - Set the sample rate to 100% for services that have a `priority` tag with the value `high`: `'[{"tags": {"priority":"high"}, "sample_rate": 1}]'`.
 
 `DD_TAGS`
-: **Default**: [] <br>
-A list of default tags to be added to every span, metric, and profile. Tags can be separated by commas or spaces, for example: `layer:api,team:intake,key:value` or `layer:api team:intake key:value`.
+: **Default**: none <br>
+A list of default tags to be added to every span, metric, and profile. Tags can be separated by commas or spaces, for example: `layer:api,team:intake,key:value` or `layer:api team:intake key:value`. Key-value pairs must be of string-convertible types.
 
 ### Agent