neomutt: make manual.txt not empty

Without elinks / w3m / lynx in the nativeBuildInputs, there are these
errors in the build:

LC_ALL=C w3m -dump -O UTF8 docs/manual.html > docs/manual.txt || \
LC_ALL=C lynx -dump -nolist -with_backspaces \
        -display_charset=us-ascii docs/manual.html > docs/manual.txt || \
LC_ALL=C elinks -dump -no-numbering -no-references \
        docs/manual.html | sed -e 's,\\001, ,g' > docs/manual.txt
/nix/store/xfbmj7sl2ikicym9x3yq7cms5qx1w39k-bash-4.4-p23/bin/bash: w3m: command not found
/nix/store/xfbmj7sl2ikicym9x3yq7cms5qx1w39k-bash-4.4-p23/bin/bash: line 1: lynx: command not found
/nix/store/xfbmj7sl2ikicym9x3yq7cms5qx1w39k-bash-4.4-p23/bin/bash: line 3: elinks: command not found

pkgs/applications/networking/mailreaders/neomutt/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchFromGitHub, gettext, makeWrapper, tcl, which, writeScript
 , ncurses, perl , cyrus_sasl, gss, gpgme, kerberos, libidn, libxml2, notmuch, openssl
-, lmdb, libxslt, docbook_xsl, docbook_xml_dtd_42, mailcap, runtimeShell, sqlite, zlib
+, lmdb, libxslt, docbook_xsl, docbook_xml_dtd_42, elinks, mailcap, runtimeShell, sqlite, zlib
 , glibcLocales
 }:
 
@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
   ];
 
   nativeBuildInputs = [
-    docbook_xsl docbook_xml_dtd_42 gettext libxml2 libxslt.bin makeWrapper tcl which zlib
+    docbook_xsl docbook_xml_dtd_42 gettext libxml2 libxslt.bin makeWrapper tcl which zlib elinks
   ];
 
   enableParallelBuilding = true;