Follow each binary format's UTF-8 rule: strict writers (CBOR/UBJSON/BJData/BSON), lenient readers (#5741)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

docs/mkdocs/docs/api/basic_json/to_bson.md

@@ -46,6 +46,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
 - Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
   exceeds 255, the maximum of the BSON binary subtype; example:
   `"subtype 70000 is too large for the BSON binary subtype (max 255)"`
+- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key is not valid
+  UTF-8 and [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled; otherwise, the bytes are
+  written unchanged
 
 ## Complexity
 
@@ -98,3 +101,6 @@ pass before anything is written.
 - Throws `out_of_range.412` and `out_of_range.415` since version 3.13.0.
 - Linear in the size of `j`, and no longer limited by the call stack for deeply nested values, since version 3.13.0.
 - `out_of_range.415` is now detected before anything is written, like the other exceptions above, since version 3.13.0.
+- Throwing `type_error.316` for a string value or object key that is not valid UTF-8 if
+  [`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled, detected before anything is written,
+  added in version 3.13.0.