Improve exception message for not found variables

[aukaurea]

Improve exception message for not found variables

Currently, when a variable is missing it shows line: Column number, it should be better if it puts the whole string source code into the error message. As it is hard to detect which when we have a number of templates.

Md. Alim Ul Karim
C# Software Architect at Crossover
Co-creator and Architect of Aurea Automatic Unit Test Solution for C#

[aukaurea]

@sharwell looking for your support.

Thank you.