Fix formatting and add required information

[c71n93]

Completed all from #7, and also added some missing information:

• Added section 2.6 about Qualifiers
• Added information about & and < attributes
• Added actual information to some sections, fixed examples

[yegor256]

@rultor merge

[rultor]

@rultor merge

@yegor256 OK, I'll try to merge now. You can check the progress of the merge here

[rultor]

@rultor merge

@c71n93 @yegor256 Oops, I failed. You can see the full log here (spent 14min)

Unpacking python3-pygments (2.3.1+dfsg-1ubuntu2.2) ...
Setting up python3-pygments (2.3.1+dfsg-1ubuntu2.2) ...
+ sudo -i pip3 install pygments
Requirement already satisfied: pygments in /usr/lib/python3/dist-packages (2.3.1)
\u001b[33mWARNING: Running pip as the 'root' user can result in broken permissions and conflicting behaviour with the system package manager. It is recommended to use a virtual environment instead: https://pip.pypa.io/warnings/venv\u001b[0m\u001b[33m
\u001b[0m--- Logging error ---
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/utils/logging.py", line 177, in emit
    self.console.print(renderable, overflow="ignore", crop=False, style=style)
  File "/usr/local/lib/python3.8/dist-packages/pip/_vendor/rich/console.py", line 1673, in print
    extend(render(renderable, render_options))
  File "/usr/local/lib/python3.8/dist-packages/pip/_vendor/rich/console.py", line 1305, in render
    for render_output in iter_render:
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/utils/logging.py", line 134, in __rich_console__
    for line in lines:
  File "/usr/local/lib/python3.8/dist-packages/pip/_vendor/rich/segment.py", line 249, in split_lines
    for segment in segments:
  File "/usr/local/lib/python3.8/dist-packages/pip/_vendor/rich/console.py", line 1283, in render
    renderable = rich_cast(renderable)
  File "/usr/local/lib/python3.8/dist-packages/pip/_vendor/rich/protocol.py", line 36, in rich_cast
    renderable = cast_method()
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/self_outdated_check.py", line 130, in __rich__
    pip_cmd = get_best_invocation_for_this_pip()
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/utils/entrypoints.py", line 58, in get_best_invocation_for_this_pip
    if found_executable and os.path.samefile(
  File "/usr/lib/python3.8/genericpath.py", line 101, in samefile
    s2 = os.stat(f2)
FileNotFoundError: [Errno 2] No such file or directory: '/usr/bin/pip3.8'
Call stack:
  File "/usr/local/bin/pip3", line 8, in <module>
    sys.exit(main())
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/cli/main.py", line 70, in main
    return command.main(cmd_args)
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/cli/base_command.py", line 101, in main
    return self._main(args)
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/cli/base_command.py", line 223, in _main
    self.handle_pip_version_check(options)
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/cli/req_command.py", line 190, in handle_pip_version_check
    pip_self_version_check(session, options)
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/self_outdated_check.py", line 236, in pip_self_version_check
    logger.warning("[present-rich] %s", upgrade_prompt)
  File "/usr/lib/python3.8/logging/__init__.py", line 1458, in warning
    self._log(WARNING, msg, args, **kwargs)
  File "/usr/lib/python3.8/logging/__init__.py", line 1589, in _log
    self.handle(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 1599, in handle
    self.callHandlers(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 1661, in callHandlers
    hdlr.handle(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 954, in handle
    self.emit(record)
  File "/usr/local/lib/python3.8/dist-packages/pip/_internal/utils/logging.py", line 179, in emit
    self.handleError(record)
Message: '[present-rich] %s'
Arguments: (UpgradePrompt(old='22.2.2', new='22.3.1'),)
+ pdd --file=/dev/null
ERROR: book.tex; PDD::Error at book.tex:494: TODO must have a leading space to become a puzzle, as this page explains: https://github.com/cqfn/pdd#how-to-format
If you can't understand the cause of this issue or you don't know how to fix it, please submit a GitHub issue, we will try to help you: https://github.com/cqfn/pdd/issues. This tool is still in its beta version and we will appreciate your feedback. Here is where you can find more documentation: https://github.com/cqfn/pdd/blob/master/README.md.
container 4a97b7356d3be9561098bd2303a38ca22e181ca2349171885de54b3cb10128d9 is dead
Sat 26 Nov 2022 03:52:43 AM CET

[yegor256]

@c71n93 try to run pdd -f /dev/null locally and you will see what is the problem. Probably, you use TODO not how we expect it to be used.

[c71n93]

@yegor256 I have fixed TODOs

[yegor256]

@rultor merge

[rultor]

@rultor merge

@yegor256 OK, I'll try to merge now. You can check the progress of the merge here

[rultor]

@rultor merge

@yegor256 Done! FYI, the full log is here (took me 1min)