clippy: add if_not_else clippy lint

[tcoratger]

@mattsse let me know what you think about this one:

Negations reduce the readability of statements.

[mattsse]

smol conflict

[tcoratger]

smol conflict

@mattsse fixed

[shekhirin]

Just so I know, are you doing these fixes automatically via clippy fix? Some of these changes are a bit invasive and touch untrivial logic (like https://github.com/paradigmxyz/reth/pull/10524/files#diff-102c8ff04a628fe92ccef5f8d0ac6eef702ad248c7a2b8e59e65cf12bb05287f), but if it's done automatically, then it's okay with me 🙂

[tcoratger]

Just so I know, are you doing these fixes automatically via clippy fix? Some of these changes are a bit invasive and touch untrivial logic (like https://github.com/paradigmxyz/reth/pull/10524/files#diff-102c8ff04a628fe92ccef5f8d0ac6eef702ad248c7a2b8e59e65cf12bb05287f), but if it's done automatically, then it's okay with me 🙂

Yeah most of them via clippy fix and the other ones via the terminal suggestion, copy and paste when clippy fix doesn't work