Add note in generated docs indicating experimental rule checks

Signed-off-by: Talon Bowler <[email protected]>

Author: daghack

frontend/dockerfile/docs/rules/_index.md

@@ -97,7 +97,7 @@ $ docker build --check .
       <td>FROM --platform flag should not use a constant value</td>
     </tr>
     <tr>
-      <td><a href="./copy-ignored-file/">CopyIgnoredFile</a></td>
+      <td><a href="./copy-ignored-file/">CopyIgnoredFile (experimental)</a></td>
       <td>Attempting to Copy file that is excluded by .dockerignore</td>
     </tr>
   </tbody>

frontend/dockerfile/docs/rules/copy-ignored-file.md

@@ -5,6 +5,11 @@ aliases:
   - /go/dockerfile/rule/copy-ignored-file/
 ---
 
+> **Note**
+>
+> This check is experimental and is not enabled by default. To enable it, see
+> [Experimental checks](https://docs.docker.com/go/build-checks-experimental/).
+
 ## Output
 
 ```text

frontend/dockerfile/linter/docs/_index.md

@@ -30,7 +30,7 @@ $ docker build --check .
   <tbody>
     {{- range .Rules }}
     <tr>
-      <td><a href="./{{ .PageName }}/">{{ .Name }}</a></td>
+      <td><a href="./{{ .PageName }}/">{{ .Name }}{{- if .Experimental }} (experimental){{- end}}</a></td>
       <td>{{ .Description }}</td>
     </tr>
     {{- end }}

frontend/dockerfile/linter/generate.go

@@ -20,11 +20,12 @@ import (
 )
 
 type Rule struct {
-	Name        string
-	Description string
-	URL         *url.URL
-	PageName    string
-	URLAlias    string
+	Name         string
+	Description  string
+	URL          *url.URL
+	PageName     string
+	URLAlias     string
+	Experimental bool
 }
 
 const tmplStr = `---
@@ -35,6 +36,13 @@ aliases:
   - {{ .Rule.URLAlias }}
 {{- end }}
 ---
+{{- if .Rule.Experimental }}
+
+> **Note**
+>
+> This check is experimental and is not enabled by default. To enable it, see
+> [Experimental checks](https://docs.docker.com/go/build-checks-experimental/).
+{{- end }}
 
 {{ .Content }}
 `
@@ -160,6 +168,10 @@ func listRules() ([]Rule, error) {
 										}
 										rule.URL = u
 									}
+								case "Experimental":
+									if basicLit, ok := kv.Value.(*ast.Ident); ok {
+										rule.Experimental = basicLit.Name == "true"
+									}
 								}
 							}
 						}