docs(inputs.snmp): Clarify the deprecation of agent tag setting (#14622)

plugins/inputs/snmp/README.md

@@ -69,6 +69,10 @@ details.
 
   ## Agent host tag; should be set to "source" for consistent usage across plugins
   ##   example: agent_host_tag = "source"
+  ## The default value is inconsistent with other plugins. Users will get a
+  ## warning that can be ignored if this is not changed. However, to have a
+  ## consistent experience, set this to "source" in your config to align with
+  ## other plugins.
   # agent_host_tag = "agent_host"
 
   ## Number of retries to attempt.

plugins/inputs/snmp/sample.conf

@@ -32,6 +32,10 @@
 
   ## Agent host tag; should be set to "source" for consistent usage across plugins
   ##   example: agent_host_tag = "source"
+  ## The default value is inconsistent with other plugins. Users will get a
+  ## warning that can be ignored if this is not changed. However, to have a
+  ## consistent experience, set this to "source" in your config to align with
+  ## other plugins.
   # agent_host_tag = "agent_host"
 
   ## Number of retries to attempt.

plugins/inputs/snmp/snmp.go

@@ -112,7 +112,7 @@ func (s *Snmp) Init() error {
 	if s.AgentHostTag != "source" {
 		models.PrintOptionValueDeprecationNotice(telegraf.Warn, "inputs.snmp", "agent_host_tag", s.AgentHostTag, telegraf.DeprecationInfo{
 			Since:  "1.29.0",
-			Notice: `should be set to "source" for consistent usage across plugins`,
+			Notice: `set to "source" for consistent usage across plugins or safely ignore this message and continue to use the current value`,
 		})
 	}