cross-referencing code & rfc: todo comments and html pages

- the rfc links back to the code now show any "todo" text that appears in the
  code. helps when looking at an rfc to find any work that may need to be done.
- html pages can now be generated to view code and rfc's side by side. clicking
  on links in one side opens the linked document in the other page, at the
  correct line number.

i'll be publishing the "dev" html version (latest commit on main branch) on the
mox website, updated with each commit. the dev pages will also link to the
latest released version.

rfc/link.go

@@ -4,6 +4,8 @@ package main
 
 // Read source files and RFC and errata files, and cross-link them.
 
+// todo: also cross-reference typescript and possibly other files. switch from go parser to just reading the source as text.
+
 import (
 	"bytes"
 	"flag"
@@ -40,6 +42,7 @@ func main() {
 		dstlineno int
 		dstisrfc  bool
 		dstrfc    string // e.g. "5322" or "6376-eid4810"
+		comment   string // e.g. "todo" or "todo spec"
 	}
 
 	// RFC-file to RFC-line to references to list of file+line (possibly RFCs).
@@ -75,6 +78,16 @@ func main() {
 						continue
 					}
 
+					var comment string
+					if strings.HasPrefix(line, "// todo") {
+						s, _, have := strings.Cut(strings.TrimPrefix(line, "// "), ":")
+						if have {
+							comment = s
+						} else {
+							comment = "todo"
+						}
+					}
+
 					srcpath := arg
 					srclineno := fset.Position(c.Pos()).Line + i
 					dir := filepath.Dir(srcpath)
@@ -104,9 +117,9 @@ func main() {
 						if _, err := os.Stat(dstpath); err != nil {
 							log.Fatalf("%s:%d: references %s: %v", srcpath, srclineno, dstpath, err)
 						}
-						r := ref{srcpath, srclineno, dstpath, dstlineno, true, rfc}
+						r := ref{srcpath, srclineno, dstpath, dstlineno, true, rfc, comment}
 						addRef(sourceLineRFCs, r.srcpath, r.srclineno, r)
-						addRef(rfcLineSources, r.dstrfc, r.dstlineno, ref{r.dstrfc, r.dstlineno, r.srcpath, r.srclineno, false, ""})
+						addRef(rfcLineSources, r.dstrfc, r.dstlineno, ref{r.dstrfc, r.dstlineno, r.srcpath, r.srclineno, false, "", comment})
 					}
 				}
 			}
@@ -162,7 +175,11 @@ func main() {
 
 				// Add link from rfc to source code.
 				for _, r := range refs {
-					line += fmt.Sprintf(" %s:%d", r.dstpath, r.dstlineno)
+					comment := r.comment
+					if comment != "" {
+						comment += ": "
+					}
+					line += fmt.Sprintf(" %s%s:%d", comment, r.dstpath, r.dstlineno)
 				}
 				if iserrata {
 					line = line[1:]