link api docs in guide

[jeyj0]

Every mention of an IHP function that I could find is now linked to the corresponding documentation. I changed the formatting where it made sense. Functions in code blocks are not linked, as that doesn't work due to markdown limitations. (It would be pretty cool though...)

[mpscholten]

Thanks 👍

cd Guide
make watch

fails for me with this error:

   |
82 | When the `callServerAction('IncrementCounterAction')` is called, it will trigger the [`action state IncrementCounterAction = do`]() haskell block to be called on the server.
   |                                                                                                                                   ^
unexpected ')'
expecting '<', URI, or white space
make: *** [Makefile:53: server-side-components.html] Error 1

[jeyj0]

No clue how I did not notice that, as I had make watch running continuously... Fixed