Add Vale linting rule for use of agentless (#739)

docs/sources/write/style-guide/word-list/index.md

@@ -25,9 +25,15 @@ This page is a work in progress.
 
 ## A
 
+<!-- vale Grafana.Agentless = NO -->
+
 ### agentless
 
-Don't use. Grafana Agent has been replaced by Grafana Alloy, so you shouldn't use agent-based terminology. Refer to [no-collector](#no-collector).
+Don't use.
+Grafana Agent has been replaced by Grafana Alloy, so you shouldn't use agent-based terminology.
+Refer to [no-collector](#no-collector).
+
+<!-- vale Grafana.Agentless = YES -->
 
 ### alert rule
 
@@ -112,7 +118,12 @@ Use this rather than _hamburger menu_ or _kebab menu_.
 
 ### no-collector
 
-Use this to refer to deployments that don't have a collector. Use this instead of _agentless_.
+<!-- vale Grafana.Agentless = NO -->
+
+Use this to refer to deployments that don't have a collector.
+Use this instead of _agentless_.
+
+<!-- vale Grafana.Agentless = YES -->
 
 ### Node Exporter
 

vale/Grafana/Agentless.yml

@@ -0,0 +1,13 @@
+extends: substitution
+message: |
+  Grafana Agent has been replaced by Grafana Alloy, so you shouldn't use agent-based terminology.
+
+  If you're talking about why and how to send signals directly from app to prefer no-collector to agentless.
+
+  This is consistent with [OTel documentation](https://opentelemetry.io/docs/collector/deployment/no-collector/).
+link: https://grafana.com/docs/writers-toolkit/write/style-guide/word-list/#no-collector
+level: warning
+action:
+  name: replace
+swap:
+  agentless: no-collector

vale/fixtures/Grafana/Agentless/.vale.ini

@@ -0,0 +1,4 @@
+StylesPath = ../../../
+MinAlertLevel = suggestion
+[*.md]
+Grafana.Agentless = YES

vale/fixtures/Grafana/Agentless/testinvalid.golden

@@ -0,0 +1,2 @@
+testinvalid.md:3:3:Grafana.Agentless:Grafana Alloy is a vendor-neutral distribution of the OpenTelemetry (OTel) Collector. It's not an agent. If you're talking about why and how to send signals directly from app to prefer no-collector to agentless. This is consistent with [OTel documentation](https://opentelemetry.io/docs/collector/deployment/no-collector/). 
+testinvalid.md:4:3:Grafana.Agentless:Grafana Alloy is a vendor-neutral distribution of the OpenTelemetry (OTel) Collector. It's not an agent. If you're talking about why and how to send signals directly from app to prefer no-collector to agentless. This is consistent with [OTel documentation](https://opentelemetry.io/docs/collector/deployment/no-collector/). 

vale/fixtures/Grafana/Agentless/testinvalid.md

@@ -0,0 +1,4 @@
+Don't use:
+
+- agentless deployment
+- agentless solution

vale/fixtures/Grafana/Agentless/testvalid.md

@@ -0,0 +1,4 @@
+Instead use:
+
+- no-collector deployment
+- no-collector solution