Tokens not getting scrubbed?

Hi there!

I recently was pointed to run the diagnostics.sh and scrub.sh tools by Elastic support, and after reviewing the resulting files noticed a few things that seem odd to me..

Namely, when scrubbing my kibana.log file, I found lines like:

```
{"grant_type":"access_token","access_token":"w/xxxxxxxxxxxxxxx"}
{"grant_type":"refresh_token","refresh_token":"w/yyyyyyyyyyyyyyyy"}
```

Except these have seemingly real token values in them (I replaced with the x's and y's above).

After scrubbing, those values are unchanged.

Is this a bug, or am I misunderstanding something about how the tool works? I would expect those to be modified to alternate values on scrubbing.

Cheers!