Sets the #hb_codepoint_t that replaces invalid entries for a given encoding when adding text to buffer.
Default is #HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT.
An #hb_buffer_t
the replacement #hb_codepoint_t
Sets the #hb_codepoint_t that replaces invalid entries for a given encoding when adding text to buffer.
Default is #HB_BUFFER_REPLACEMENT_CODEPOINT_DEFAULT.