Update goto-instrument man page

With command-line help being complete, help2man was used to create an updated
list of options for goto-instrument's man page. Moving forward, automated
checks for man-page completeness will be put in place so that future changes to
the command line will have to be reflected as part of the changing commit.

Some documentation was moved from files in doc/architectural that
weren't actually included in any rendered documentation.

All code snippets are formatted using:
```
clang-format --assume-filename=tmp.c --style=LLVM - | \
  source-highlight -s c -f groff_man | tail -n+3 | head -n- 2 | sed 's/^ //'
```

Fixes: #6973

Author: tautschnig