Use the main Web site version of the docs for KaiOS apps

Simon's build infrastructure doesn't have Halibut available on the same
system as Emscripten, which means that the normal KaiOS build can't
build the documentation.  At present, though, the version of the
documentation that's built for the Web page is perfectly acceptable for
KaiOS as well, so we may as well seed the KaiOS build directory with
that.

This is slightly unfortunate because it means that it's difficult to
make changes only to the KaiOS documentation, and I'd like to be able to
do that eventually.  We can cross that bridge once Halibut has the
features I want.

Buildscr

@@ -133,6 +133,10 @@ endif
 # have the right dependencies installed for Emscripten, I do this by a
 # delegation.
 ifneq "$(NOJS)" yes then
+  # The Emscripten delegate doesn't have Halibut, so provide the HTML
+  # docs for the KaiOS apps to use.
+  in puzzles do mkdir -p build-kaios/help/en
+  in puzzles do cp -Rv doc/* build-kaios/help/en
   delegate emscripten
     in puzzles do emcmake cmake -B build-emscripten $(web_unfinished_option) .
     in puzzles/build-emscripten do make -j$(nproc) VERBOSE=1