Fixes various issues in documentation:
- replaces HTML anchor tags in markdown headings by markdown heading IDs.
- replaces HTML linebreaks by newline commands
- replaces \htmlonly commands for image resizing by the width argument in \image commands
- replaces
- uses more unique identifiers for references
- uses stable references for driver documentation
- fix broken links to external HTML documents
- replaces the TOC link in headers by a back to TOC link below each section
- replaces ``` fenced code blocks by ~~~
The link to nodemcu-devkit-v1.0 was missing 'h' in 'http'.
Other links were missing 'http://' or 'https://' and were pointing
to non-existing components on RIOT's web site.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
