DOCS: Documentation inline replacements (#2083)

Co-authored-by: Tom Limoncelli <tlimoncelli@stackoverflow.com>

build/generate/featureMatrix.go

@@ -1,11 +1,12 @@
 package main
 
 import (
-	"sort"
-
 	"github.com/StackExchange/dnscontrol/v3/providers"
 	_ "github.com/StackExchange/dnscontrol/v3/providers/_all"
 	"github.com/fbiville/markdown-table-formatter/pkg/markdown"
+	"os"
+	"sort"
+	"strings"
 )
 
 func generateFeatureMatrix() error {
@@ -16,7 +17,12 @@ func generateFeatureMatrix() error {
 		return err
 	}
 
-	_ = markdownTable
+	replaceInlineContent(
+		"documentation/providers.md",
+		"<!-- provider-matrix-start -->",
+		"<!-- provider-matrix-end -->",
+		markdownTable,
+	)
 
 	return nil
 }
@@ -277,3 +283,29 @@ type FeatureMatrix struct {
 	Features  []string
 	Providers map[string]FeatureMap
 }
+
+func replaceInlineContent(
+	file string,
+	startMarker string,
+	endMarker string,
+	newContent string,
+) {
+	contentBytes, err := os.ReadFile(file)
+	if err != nil {
+		panic(err)
+	}
+	content := string(contentBytes)
+
+	start := strings.Index(content, startMarker)
+	end := strings.Index(content, endMarker)
+
+	newContentString := startMarker + "\n" + newContent + endMarker
+	newContentBytes := []byte(newContentString)
+	contentBytes = []byte(content)
+	contentBytes = append(contentBytes[:start], append(newContentBytes, contentBytes[end+len(endMarker):]...)...)
+
+	err = os.WriteFile(file, contentBytes, 0644)
+	if err != nil {
+		panic(err)
+	}
+}