Examples for UDT formatters in the documentation won't work with compiled format strings

[erinacio]

The examples in API Reference :: Formatting User-Defined Types use format_context for the second parameter of format method. This won't work with FMT_COMPILE(...) or ..._cf as the format context type with compiled format string would be a different one. This is neither documented in API Reference :: Formatting User-Defined Types nor in API Reference :: Format String Compilation, and the compilation error message is error: call to 'write' is ambiguous which looks confusing to me, taking me half an hour to find the root cause. Would be great if such information is added to the documentation and the examples for udt formatters are updated for supporting compiled format strings.

[vitaut]

Clarified in 95e1ea5. Thanks for the suggestion.