Fix tiny bug in misc_util.py

[youknowqyh]

References to other Issues or PRs or Relevant literature

Brief description of what is fixed or changed

When I run the following code, the program won't work correctly:

>>> from pydatastructs import OneDimensionalArray
>>> from pydatastructs import OneDimensionalArray as ODA
>>> ODA(int, 5, backend='Python')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/yuhaoq/yuhaoq/noob/pydatastructs/pydatastructs/linear_data_structures/arrays.py", line 78, in __new__
    raise_if_backend_is_not_python(
  File "/Users/yuhaoq/yuhaoq/noob/pydatastructs/pydatastructs/utils/misc_util.py", line 33, in raise_if_backend_is_not_python
    raise ValueError("As of {} version, only {} backend is supported for {} API".format(
ValueError: As of 1.0.1-dev version, only Python backend is supported for <class 'pydatastructs.linear_data_structures.arrays.OneDimensionalArray'> API

I figured out the reason behind is that in raise_if_backend_is_not_python, the type of backend is str, but the type of Backend.Python is Backend. So in order to solve it, we should convert the type of Backend.Python to str

Other comments

[czgdp1807]

This is not a bug. It is what it is.