* Cache takes ownership of input data

The cache example now owns the data, and not static references, as mentioned in al8n#48 Also variable names are modified to explain their usage.

* Update sync_example.rs

The cache example now owns the data, and not static references, as mentioned in al8n#48 Also variable names are modified to explain their usage.

While reviewing the code I was a confused by the name num_entries which suggest an integer while actually a fractional number is used. Changing this to usize makes the function call 7 machine code instructions shorter and the function body longer 5 instructions longer (from 65 to 70, as checked by the compiler explorer https://godbolt.org/ ). So with improved code readability also 2 instructions less are needed.

…odifying field of interest (al8n#52)

…-edition 2021

A single character contribution.