Handle no space between param name and colon

[lagru]

Consider this docstring

from numpydoc.docscrape import NumpyDocString

def foo(x):
    """Function docstring.
    
    Parameters
    ----------
    x: int
        Some description
    """

NumpyDocString(foo.__doc__)["Parameters"]

returns

[Parameter(name='x: int', type='', desc=['Some description'])]

Notice how the type of the parameter is empty! While the official syntax requires that the colon is preceded by a space, it's a typo that's very easy to miss and is very annoying in context of docstub. This case should be detected and either be warned about or handled gracefully.

[lagru]

Related numpy/numpydoc#78. The general consensus seems to be to lint this prior with numpydoc lint. However, that linter doesn't seem to detect this specific issue.