Add a comment to clarify which ConvertWOFF2ToTTF should be preferred

src/woff2_dec.h

@@ -29,11 +29,13 @@ size_t ComputeWOFF2FinalSize(const uint8_t *data, size_t length);
 // Decompresses the font into the target buffer. The result_length should
 // be the same as determined by ComputeFinalSize(). Returns true on successful
 // decompression.
+// DEPRECATED; please prefer the version that takes a WOFF2Out*
 bool ConvertWOFF2ToTTF(uint8_t *result, size_t result_length,
                        const uint8_t *data, size_t length);
 
 // Decompresses the font into out. Returns true on success.
 // Works even if WOFF2Header totalSfntSize is wrong.
+// Please prefer API.
 bool ConvertWOFF2ToTTF(const uint8_t *data, size_t length,
                        WOFF2Out* out);