Doc examples not helpful in std::fmt

[sophiajt]

Was just trying to read through std::fmt to understand how format values to a particular decimal point. I came across this set of examples, which don't do a good job of explaining the output of each, so it's difficult to visually pattern match what I type in to what comes out:

// Hello {arg 0 (x)} is {arg 1 (0.01) with precision specified inline (5)}
println!("Hello {0} is {1:.5}", "x", 0.01);

// Hello {arg 1 (x)} is {arg 2 (0.01) with precision specified in arg 0 (5)}
println!("Hello {1} is {2:.0$}", 5, "x", 0.01);

// Hello {arg 0 (x)} is {arg 2 (0.01) with precision specified in arg 1 (5)}
println!("Hello {0} is {2:.1$}", "x", 5, 0.01);

// Hello {next arg (x)} is {second of next two args (0.01) with precision
//                          specified in first of next two args (5)}
println!("Hello {} is {:.*}",    "x", 5, 0.01);

// Hello {next arg (x)} is {arg 2 (0.01) with precision
//                          specified in its predecessor (5)}
println!("Hello {} is {2:.*}",   "x", 5, 0.01);

// Hello {next arg (x)} is {arg "number" (0.01) with precision specified
//                          in arg "prec" (5)}
println!("Hello {} is {number:.prec$}", "x", prec = 5, number = 0.01);

[knight42]

Sorry for the mess 😅 I guess it is clearer now.