Feature Request: Warn when not using return value of pure method

[adameska]

Product and Version Used: rosylnator, 2019

Steps to Reproduce: string testString = "123 test"; testString.Replace("123", ""); output(testString);

Actual Behavior: no warning that "Return value of pure method is not used"

Expected Behavior: Warn me! "Return value of pure method is not used"

[adameska]

This bit me recently, trying to use 2019 without Resharper and would be nice to catch these cases too!

[NN---]

It would be nice to support also methods annotated with JetBrains.Annotations.PureAttribute.