Invalid documentation of borrowed references#154

https://github.com/nrc/r4cppp/blob/3cea93b7e2c18d131c0ad10b3d4d9c3638aece75/borrowed.md?plain=1#L76 Ignoring irrelevant grokking, the documentation claims only one mutable borrowed ptr can be taken and that a non mutable ptr cannot be borrowed if already a mutable borrowed ptr exists - both seem incorrect. See the output I'm getting (please ignore the irrelevant grokking) when running below: https://github.com/lamvak/grokking-rust/blob/e01839a2d589f6a57c4058bbd37be8f908b0280b/first_rust_vs/src/main.rs#L23 > C:\Users\lamva\Documents\GitHub\grokking-rust\first_rust_vs>cargo run > Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.15s > Running `target\debug\first_rust_vs.exe` > Fib(1) = 1 > Fib(5) = 8 > Fib(10) = 89 > from foo: 5 > from foo: 5 > from foo2: 5 > from foo: 5 > and the new val: 15