Incorrect summary comments on Warn.If overloads

[rouacke]

I believe a couple Warn.If overloads have incorrect summary comments.

https://github.com/nunit/nunit/blob/master/src/NUnitFramework/framework/Warn.cs#L335

https://github.com/nunit/nunit/blob/master/src/NUnitFramework/framework/Warn.cs#L335

The summary comments on those overloads read:

Asserts that a condition is true. If the condition is false, a warning is issued.

However, the method bodies read:

Warn.If(condition, Is.True, ...);

They log a warning if the condition is true.

The summary comment seems to be correct on other overloads:

Asserts that a condition is false. If the condition is true a warning is issued.

[rprouse]

Good catch. That code has been there forever. It is surprising no one has noticed before you!