fix: Convert slab plugin to new sample.conf. (#11181)

plugins/inputs/slab/README.md

@@ -13,7 +13,7 @@ If the HOST_PROC environment variable is set, Telegraf will use its value instea
 
 ## Configuration
 
-```toml
+```toml @sample.conf
 # Get slab statistics from procfs
 [[inputs.slab]]
   # no configuration - please see the plugin's README for steps to configure

plugins/inputs/slab/sample.conf

@@ -0,0 +1,4 @@
+# Get slab statistics from procfs
+[[inputs.slab]]
+  # no configuration - please see the plugin's README for steps to configure
+  # sudo properly

plugins/inputs/slab/slab.go

@@ -1,3 +1,4 @@
+//go:generate ../../../tools/readme_config_includer/generator
 //go:build linux
 // +build linux
 
@@ -6,6 +7,7 @@ package slab
 import (
 	"bufio"
 	"bytes"
+	_ "embed"
 	"errors"
 	"fmt"
 	"os"
@@ -20,13 +22,21 @@ import (
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
 
+// DO NOT REMOVE THE NEXT TWO LINES! This is required to embedd the sampleConfig data.
+//go:embed sample.conf
+var sampleConfig string
+
 type SlabStats struct {
 	Log telegraf.Logger `toml:"-"`
 
 	statFile string
 	useSudo  bool
 }
 
+func (*SlabStats) SampleConfig() string {
+	return sampleConfig
+}
+
 func (ss *SlabStats) Init() error {
 	return nil
 }