remove hard dependency and configure spelling extension only if it can load enchant properly

import sys

import os

has_enchant = False

try:

    import enchant

    has_enchant = True

except:

    pass

# If extensions (or modules to document with autodoc) are in another directory,

# add these directories to sys.path here. If the directory is relative to the

# documentation root, use os.path.abspath to make it absolute, like shown here.

# configure spelling extension if present

import importlib.util

spelling_spec = importlib.util.find_spec("sphinxcontrib.spelling")

if spelling_spec:

if spelling_spec and has_enchant:

    extensions.append('sphinxcontrib.spelling')

    spelling_lang='en_US'