[EC69] - check relevance of this rule

[dedece35]

like in python issue green-code-initiative/creedengo-python#21, check if implemented EC69 rule in C# plugin is relevant or not

[vdebellabre]

For loops in Python match foreach loops in C#, and don't trigger a warning with our rule implementation.

foreach (int i in Enumerable.Range(0, 10)) // Compliant, evaluated once

For loops however are equivalent to for loops in C/C++, and evaluate function calls in conditions at every iteration, this is what our rule covers.

for (int i = 0; i < GetValue(); i++) // Non compliant, loop invariant function in loop condition

This is also the case for while and do-while loops, our rule implementation covers those too.