Set asserts in kitchen_sink_proc_macro.rs

[makorne]

I tried the kitchen_sink_proc_macro example and found that custom cache has hits: None and misses: None

target/debug/kitchen_sink_proc_macro`

** default cache with default name ** hits: Some(2) misses: Some(4)

** default cache with explicit name ** hits: Some(1) misses: Some(1)

** specific cache ** hits: Some(19) misses: Some(21)

** custom cache ** hits: None misses: None

Looks like Custom cache does not work. I set asserts for this example please check it.