man: Pass --regex/--wildcard on to whatis/apropos

Fixes https://gitlab.com/man-db/man-db/-/issues/13.

* src/man.c (do_extern): Pass `-r` or `-w` options to the external
program if necessary.
* man/man1/man.man1 (Main modes of operation): Document that `-f` and
`-k` are still only approximately equivalent to `whatis` and `apropos`
respectively (since `man` accepts slightly different options).
* NEWS.md: Document this.

1 files changed, 2 insertions, 0 deletions

diff --git a/NEWS.md b/NEWS.md
index 9f655f38..ac621fc6 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -22,6 +22,8 @@ Improvements:
    positives.
  * Take advantage of newer `groff` facilities to implement `man
    --no-hyphenation` and `man --no-justification`, if available.
+ * `man -f` and `man -k` now pass any `-r`/`--regex` or `-w`/`--wildcard`
+   options on to `whatis` and `apropos` respectively.
 
 man-db 2.11.2 (8 January 2023)
 ==============================