Bug#31798: boot-floppies: undeclared dependency on sp

[<jrv@vanzandt.mv.com>]

Package: boot-floppies
Version: 2.1.4

documentation/Makefile calls for nsgmls, which comes from the sp package.

-- System Information
Debian Release: 2.0
Kernel Version: Linux vanzandt 2.1.132 #5 Tue Dec 29 15:31:03 EST 1998 i686 unknown

Versions of the packages boot-floppies depends on:
ii  libc6-pic       2.0.7v-1       The GNU C library version 2 (PIC library)
ii  slang1-pic      1.2.2-2        The S-Lang programming library, shared libra
ii  sysutils        1.3.2          Miscellaneous small system utilities.
ii  makedev         2.3.1-10       Creates special device files in /dev.
ii  newt0.25        0.25-3         Not Erik's Windowing Toolkit - text mode win
ii  newt0.25-dev    0.25-3         Developer's toolkit for newt windowing libra
ii  popt            1.0-4          C library for parsing command line parameter
ii  zlib1g          1.1.3-2        compression library - runtime
ii  zlib1g-dev      1.1.3-2        compression library - development
ii  recode          3.4.1-11       Character set conversion utility.