[bug] KeyError: 'href' error

[DariuszPorowski]

If html output contains namespace e.g. <a xlink:href="./foo/bar/"> then file['href'] from loop:

mkdocs-exclude-unused-files/mkdocs_exclude_unused_files/plugin.py

Line 61 in aceb9e2

for file in soup.find_all('a'):

throw

ERROR    -  Error building page 'README.md': 'href'
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.10.10/x64/bin/mkdocs", line 8, in <module>
    sys.exit(cli())
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/mkdocs/__main__.py", line 250, in build_command
    build.build(cfg, dirty=not clean)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/mkdocs/commands/build.py", line 329, in build
    _build_page(file.page, config, doc_files, nav, env, dirty)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/mkdocs/commands/build.py", line 234, in _build_page
    output = config.plugins.run_event('post_page', output, page=page, config=config)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/mkdocs/plugins.py", line 520, in run_event
    result = method(item, **kwargs)
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/mkdocs_exclude_unused_files/plugin.py", line 62, in on_post_page
    self.asset_files.discard(str(Path(path.join(path.dirname(page.file.abs_dest_path), unquote(file['href']))).resolve()))
  File "/opt/hostedtoolcache/Python/3.10.10/x64/lib/python3.10/site-packages/bs4/element.py", line 1529, in __getitem__
    return self.attrs[key]
KeyError: 'href'

proposed solution:

for file in soup.find_all("a", {'href': True}):

it will scraping only valid links.

fix with abstraction proposed in: #1