Control float/double formatting with `{any}`

[Sze]

As explained here:

Idiomatic Complex Formatting

The idiomatic way of implementing custom formatting would be to implement a format function. std.fmt.format, which std.debug.print and other formatting functions that take a format string with placeholders are derived from, has this to say in its doc comment: If a formatted user type contains a function of the type pub fn format( value: ?, comptime fmt: []const u8, options: std.fmt.FormatOptions, writer: anytype, ) !void with ? being the type formatted, this function will be call…

You can add a format function to your type Foo or you could use the std.fmt.Formatter and use a freestanding function to explicitly format an argument to a printing function.