feat(cli): add new '--toc' option

This flag creates a new h3 at the top of the html file and below it generates list items with links as heading numbers and text for the heading

Author: xnacly

cli/cli.go

@@ -22,7 +22,12 @@ var OPTIONS []Flag = []Flag{
 	{
 		"silent",
 		false,
-		"disables info logs, reduces output significantly ",
+		"disables info logs, reduces output significantly",
+	},
+	{
+		"toc",
+		false,
+		"generates a table of contents at the top of the output with links to the headings",
 	},
 	{
 		"keep-temp",

doc/Usage.md

@@ -39,5 +39,6 @@ exit status 1
 | `--keep-temp`            | stops fleck from removing temporary files              | false         |
 | `--preprocessor-enabled` | enables the preprocessor and therefore macro expansion | false         |
 | `--shell-macro-enabled`  | enables the `@shell` macro                             | false         |
+| `--toc`                  | generates a table of contents                          | false         |
 
 See [Macros](./Macros.md) for more information about the preprocessor and macros.