docs(encoder): correct the multi-line string claim

Assisted-by: DeepSeek V4.1 Flash

docs/API.md

@@ -412,10 +412,9 @@ omitted, because TOML forbids an empty `[[a]]`. Other empty arrays emit as
 ### Long strings
 
 By default every string is emitted as a basic `"..."` string with the escapes
-TOML requires, and a string containing a newline is emitted as an escaped
-multi-line basic string. `UseLiteralMultiline(threshold)` switches strings that
-contain a newline and are at least `threshold` bytes long to the literal
-`'''...'''` form, which carries the newlines verbatim:
+TOML requires, a newline among them as `\n`. `UseLiteralMultiline(threshold)`
+switches strings that contain a newline and are at least `threshold` bytes long
+to the literal `'''...'''` form, which carries the newlines verbatim:
 
 ```go
 out, err := interpres.NewEncoder().UseLiteralMultiline(80).Marshal(cfg)

interpres.go

@@ -261,14 +261,14 @@ func MarshalContext(ctx context.Context, v any) ([]byte, error) {
 
 // An Encoder encodes Go values into TOML.
 //
-// All options default to behaviour that preserves byte-for-byte compatibility
-// with previous releases and passes the toml-test compliance suite:
+// All options default to the behaviour earlier releases used, and the defaults
+// pass the toml-test compliance suite in both directions:
 //
 //	GroupByKind:        true  (scalars first, then tables, then arrays of tables)
 //	OmitEmptyArrays:    false (a nil/empty []string slice emits [] as a value;
 //	                          a nil/empty []Item struct slice is still skipped)
-//	LiteralMultilineAt: 0     (always emit basic multi-line strings with
-//	                          escape sequences, never literal ones)
+//	LiteralMultilineAt: 0     (always emit the escaped basic form, never a
+//	                          literal one)
 //
 // Use the chainable option methods to opt out. The option state is private;
 // callers that need the underlying knobs reach for the methods rather than