Floss: Fix Floss doc

* Fix broken links for packages/modules/bluetooth
* Use backticks to format code
* When generated in to Rust code, square brackets are put inside #doc[]
  attribute which becomes a link. Use parentheses in C docs that will be
  generated into Rust code.

Bug: 67853426
Tag: #floss
Test: Build Floss doc with `build.py --target doc`

Change-Id: Icd2d02cf714a1e5b6e0616648586049a59090092