* src/search.c (Fmatch_data): Note quirk about non-matching
optional groups in the doc string (bug#29343).
if the last match was on a buffer; integers or nil if a string was matched.
Use `set-match-data' to reinstate the data in this list.
+Note that non-matching optional groups at the end of the regexp are
+elided instead of being represented with two `nil's each. For instance:
+
+ (progn
+ (string-match "^\\(a\\)?\\(b\\)\\(c\\)?$" "b")
+ (match-data))
+ => (0 1 nil nil 0 1)
+
If INTEGERS (the optional first argument) is non-nil, always use
integers (rather than markers) to represent buffer positions. In
this case, and if the last match was in a buffer, the buffer will get