Fix minor grammatical errors in documentation

[famouswizard]

Fix minor grammatical errors in documentation

Description

Two minor grammatical issues in the documentation files docs/src/fft/benchmarks.md and docs/src/plonk/implementation.md. These errors could cause confusion for readers and reduce the professionalism of the documentation.

1. In docs/src/fft/benchmarks.md, the sentence:

   "Those cases which were greater than 30 seconds were marked respectively as they're too slow and weren't worth to be benchmarked."
   was corrected to:
   "Those cases which were greater than 30 seconds were marked respectively as they're too slow and weren't worth benchmarking."
   Explanation: The phrase "weren't worth to be benchmarked" is grammatically incorrect. The correct phrase is "weren't worth benchmarking," which improves the readability and clarity of the sentence.

2. In docs/src/plonk/implementation.md, the sentence:

   "Let's brake it down."
   was corrected to:
   "Let's break it down."
   Explanation: The word "brake" was mistakenly used instead of "break." "Brake" refers to a stopping mechanism, while "break" is the correct word in this context, meaning to divide or analyze something in parts.

These changes improve the clarity and professionalism of the documentation.

Type of change

Please delete options that are not relevant.

• Optimization

Checklist

• Documentation has been added/updated.