fix EDS Signal NameError

[willson556]

Fix the following crash:

Traceback (most recent call last):
  File "/usr/lib/python3.10/runpy.py", line 196, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/lib/python3.10/runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "/home/.../python3.10/site-packages/canmatrix/cli/convert.py", line 163, in <module>
    sys.exit(cli_convert())
  File "/home/.../python3.10/site-packages/click/core.py", line 1485, in __call__
    return self.main(*args, **kwargs)
  File "/home/.../python3.10/site-packages/click/core.py", line 1406, in main
    rv = self.invoke(ctx)
  File "/home/.../python3.10/site-packages/click/core.py", line 1269, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/.../python3.10/site-packages/click/core.py", line 824, in invoke
    return callback(*args, **kwargs)
  File "/home/.../python3.10/site-packages/canmatrix/cli/convert.py", line 158, in cli_convert
    canmatrix.convert.convert(infile, outfile, **options)
  File "/home/.../python3.10/site-packages/canmatrix/convert.py", line 69, in convert
    dbs = canmatrix.formats.loadp(infile, **options)
  File "/home/.../python3.10/site-packages/canmatrix/formats/__init__.py", line 71, in loadp
    return load(fileObject, import_type, key, **options)
  File "/home/.../python3.10/site-packages/canmatrix/formats/__init__.py", line 94, in load
    dbs[key] = module_instance.load(file_object, **options)  # type: ignore
  File "/home/.../python3.10/site-packages/canmatrix/formats/eds.py", line 245, in load
    new_sig = canmatrix.Signal(signal_name, size=bit_length, start_bit=current_bit_start)
NameError: name 'canmatrix' is not defined. Did you mean: 'CanMatrix'?

Also, fix the type hint on load().