Use string.Contains instead of IndexOf comparison

Proprietary

Replace s.IndexOf(x) >= 0 with s.Contains(x) and s.IndexOf(x) == -1 with !s.Contains(x).

OpenRewrite.Recipes.CSharp.CodeQuality.Style.UseStringContains

mod run . --recipe=OpenRewrite.Recipes.CSharp.CodeQuality.Style.UseStringContains

Install it once, then run it on every repository under the current directory. New to the Moderne CLI? Set it up.