extension: Get comment from symbol database non markdown listed files
extension: Get comment from symbol database non markdown listed files

For example if you have in the sitemap

```
gi-index
        somesource.h
```

The page comment should be retrieved from the comments database and not
from any markdown file

hotdoc/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,thiblahute/hotdoc,hotdoc/hotdoc,thiblahute/hotdoc,thiblahute/hotdoc