Use delete-char instead of backward-delete-char

Use delete-char instead of backward-delete-char

* lisp/bs.el (bs-delete):
* lisp/dired-aux.el (dired-show-file-type):
* lisp/emulation/viper-cmd.el (viper-insert-prev-from-insertion-ring):
* lisp/man.el (Man-fontify-manpage, Man-cleanup-manpage):
* lisp/net/mailcap.el (mailcap-parse-mailcap):
* lisp/progmodes/antlr-mode.el (antlr-insert-makefile-rules):
* lisp/textmodes/reftex-ref.el (reftex-reference):
* lisp/vc/emerge.el:
* lisp/woman.el (woman-man-buffer):
* test/src/fns-tests.el (fns-tests-hash-buffer):
Replace some calls to backward-delete-char with delete-char (negating
the argument) since the former is intended for interactive use.
This silences most of the interactive-only warnings.