log/slog: JSONHandler doesn't use special source format

Fixes #60329

Change-Id: Idb19da4830fa14c459bedbf143d550ce7c1dfdbd
Reviewed-on: https://go-review.googlesource.com/c/go/+/496815
Reviewed-by: Jonathan Amsterdam <[email protected]>
Run-TryBot: Jonathan Amsterdam <[email protected]>
Reviewed-by: Alan Donovan <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>

Author: seankhliao

src/log/slog/json_handler.go

@@ -66,8 +66,7 @@ func (h *JSONHandler) WithGroup(name string) Handler {
 // and the value of [Level.String] is output.
 //
 // If the AddSource option is set and source information is available,
-// the key is "source"
-// and the value is output as "FILE:LINE".
+// the key is "source", and the value is a record of type [Source].
 //
 // The message's key is "msg".
 //