innobase/include/ut0mem.h:
  Improve documentation of ut_strlenq(), ut_strcpyq() and ut_memcpyq()
innobase/include/ut0mem.ic:
  Improve documentation of ut_strlenq()
innobase/row/row0mysql.c:
  row_discard_tablespace_for_mysql(): Add quotes around table_name
  in DISCARD_TABLESPACE_PROC (Bug #5851)
innobase/ut/ut0mem.c:
  Improve documentation of ut_strcpyq() and ut_memcpyq()