Add format_docs command for documentation trailing space formatting

Makefile

@@ -37,6 +37,9 @@ fmt:
 	@gofmt -s -w .
 	@gci write --custom-order -s standard -s "prefix(github.com/sagernet/)" -s "default" .
 
+fmt_docs:
+	go run ./cmd/internal/format_docs
+
 fmt_install:
 	go install -v mvdan.cc/gofumpt@latest
 	go install -v github.com/daixiang0/gci@latest

cmd/internal/format_docs/main.go

@@ -0,0 +1,117 @@
+package main
+
+import (
+	"bytes"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/sagernet/sing-box/log"
+)
+
+func main() {
+	err := filepath.Walk("docs", func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if info.IsDir() {
+			return nil
+		}
+		if !strings.HasSuffix(path, ".md") {
+			return nil
+		}
+		return processFile(path)
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+func processFile(path string) error {
+	content, err := os.ReadFile(path)
+	if err != nil {
+		return err
+	}
+
+	lines := strings.Split(string(content), "\n")
+	modified := false
+	result := make([]string, 0, len(lines))
+
+	inQuoteBlock := false
+	materialLines := []int{} // indices of :material- lines in the block
+
+	for _, line := range lines {
+		// Check for quote block start
+		if strings.HasPrefix(line, "!!! quote \"") && strings.Contains(line, "sing-box") {
+			inQuoteBlock = true
+			materialLines = nil
+			result = append(result, line)
+			continue
+		}
+
+		// Inside a quote block
+		if inQuoteBlock {
+			trimmed := strings.TrimPrefix(line, "    ")
+			isMaterialLine := strings.HasPrefix(trimmed, ":material-")
+			isEmpty := strings.TrimSpace(line) == ""
+			isIndented := strings.HasPrefix(line, "    ")
+
+			if isMaterialLine {
+				materialLines = append(materialLines, len(result))
+				result = append(result, line)
+				continue
+			}
+
+			// Block ends when:
+			// - Empty line AFTER we've seen material lines, OR
+			// - Non-indented, non-empty line
+			blockEnds := (isEmpty && len(materialLines) > 0) || (!isEmpty && !isIndented)
+			if blockEnds {
+				// Process collected material lines
+				if len(materialLines) > 0 {
+					for j, idx := range materialLines {
+						isLast := j == len(materialLines)-1
+						resultLine := strings.TrimRight(result[idx], " ")
+						if !isLast {
+							// Add trailing two spaces for non-last lines
+							resultLine += "  "
+						}
+						if result[idx] != resultLine {
+							modified = true
+							result[idx] = resultLine
+						}
+					}
+				}
+				inQuoteBlock = false
+				materialLines = nil
+			}
+		}
+
+		result = append(result, line)
+	}
+
+	// Handle case where file ends while still in a block
+	if inQuoteBlock && len(materialLines) > 0 {
+		for j, idx := range materialLines {
+			isLast := j == len(materialLines)-1
+			resultLine := strings.TrimRight(result[idx], " ")
+			if !isLast {
+				resultLine += "  "
+			}
+			if result[idx] != resultLine {
+				modified = true
+				result[idx] = resultLine
+			}
+		}
+	}
+
+	if modified {
+		newContent := strings.Join(result, "\n")
+		if !bytes.Equal(content, []byte(newContent)) {
+			log.Info("formatted: ", path)
+			return os.WriteFile(path, []byte(newContent), 0o644)
+		}
+	}
+
+	return nil
+}