Modified Error messages

[pratikgl]

Modified error messages and made them more clear

References to other Issues or PRs or Relevant literature

The previous error messages were quite vague which pretty much said: "something went wrong". I have made changes in the error message so the user would know what exactly went wrong.

Brief description of what is fixed or changed

For example instead of saying 1D array cannot be created due to incorrect information it would now say Data type is not defined or Too few arguments to create a 1D array, pass either size of the array or list of elements or both.

Other comments

[codecov]

Codecov Report

Merging #411 (dc98ba4) into master (f391ab6) will increase coverage by 0.001%.
The diff coverage is 100.000%.

@@              Coverage Diff              @@
##            master      #411       +/-   ##
=============================================
+ Coverage   98.620%   98.622%   +0.001%     
=============================================
  Files           26        26               
  Lines         3407      3411        +4     
=============================================
+ Hits          3360      3364        +4     
  Misses          47        47               

Impacted Files	Coverage Δ
pydatastructs/linear_data_structures/arrays.py	100.000% <100.000%> (ø)

[czgdp1807]

Thanks @pratikgl