make examples work and help texts more consistent and readable.

This pull request should make: 
 * the CLI command examples work
 * CLI help texts more consistent 
 * and readable

This pull request changes: `core/modules/utils/fakedom.js` `formattedTextContent` handler.
Since it is only used to create command line output, there should be no side effects. 

`pre` and `li` now create an indentation with 4 spaces, which imo makes the help texts much more readable. The formatting in the TW output is not affected. 

see the difference with: 

```
node tiddlywiki.js --help     ... new
tiddlywiki --help              ... old if tiddlywiki is installed globally
or
node tiddlywiki.js --help server
tiddlywiki --help server
...
```
May be because environment variables look like this `%TW_SERVE_EDITION_PATH%` in .cmd 
But you definitely get an error message if you run it from CLI.

```
D:\git\tiddly\tiddlywiki\TiddlyWiki5 [better-cli-help]> tiddlywiki .\editions\tw5.com-server --server 8080 $:/core/save/all text/plain text/html
In Zeile:1 Zeichen:52
+ tiddlywiki .\editions\tw5.com-server --server 8080 $:/core/save/all text/plain t ...
+                                                    ~~
Ungültiger Variablenverweis. Nach "$" folgte kein Zeichen, das für einen Variablennamen gültig ist. Verwenden Sie ggf. "${}", um den Namen zu begrenzen.
    + CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : InvalidVariableReference
```

The message is German, but you can see the `~~` below the `$` ... It wants to use it as an environment variable.