Added raspberry pi perf apt command.
Removed legacy note about cargo-flamegraph:
The command doesn't seem to work,
the note will still be in git history if need be.
Main intent was to put the 'cargo install flamegraph' in what subjectively appears to be a clearer location (happy to drop the other changes if they're note appropriate).
Added raspberry pi perf apt command. Removed legacy note about cargo-flamegraph: The command doesn't seem to work, the note will still be in git history if need be.