chore: fix spelling issues

[Guayaba221]

an validation - a validation

tot the - to the

but not cannot - but cannot x2

a RLPx - an RLPx

A Rplx - An Rplx

Ethereum Wire Protocol - Ethereum Wire Protocol - deleted space

When pronounced out loud, “RPLx” starts with the vowel sound [ɑr], similar to "ar-P-L-x." According to the rule that we use "an" before vowel sounds, the correct phrase is "an RPLx," not "a RPLx."

I tried my best , and I hope it was helpful to you ! Thanks

[mattsse]

I let this one slide because this actually includes multiple fixes