[docs] SDK demo cosmetics.

Made the example a little bit smaller by removing some unneeded
boilerplate.
(Possible thanks to Dune 3's `glob_files_rec`.)

Also, the example now showcases `group-theory` instead of Coqoban.
Mainly because we already have Coqoban as an addon.

examples/.gitignore

 _build
 nahas_tutorial.html
+
+# This is quite meaningless for examples
+package-lock.json
\ No newline at end of file

examples/sdk-demo/.gitignore

+workdir
\ No newline at end of file

examples/sdk-demo/Makefile

 
-REPO = https://github.com/coq-community/coqoban
+REPO = https://github.com/coq-contribs/group-theory.git
 WORKDIR = workdir
 
 PATH := $(PWD)/bin:$(PATH)
 export PATH
 
 build: $(WORKDIR)
+	cp dune-files/dune $(WORKDIR)/
 	# Use current workspace, not jsCoq's
 	dune build --root .
 

examples/sdk-demo/dune

@@ -2,9 +2,9 @@
 (rule
  (targets coq-pkgs)
  (deps
-  (package coq-coqoban))
+  (glob_files_rec "*.vo"))
  (action
-  (run npx %{env:pkgtool=jscoq} build workdir --top Coqoban
-       --package coq-pkgs/coqoban.coq-pkg)))
+  (run npx %{env:pkgtool=jscoq} build workdir --top GroupTheory
+       --package coq-pkgs/group-theory.coq-pkg)))
 
 (dirs workdir)

examples/sdk-demo/dune-files/dune

+; Copied to `workdir/` by Makefile
+
+(coq.theory
+ (name GroupTheory)
+ (synopsis "Elements of Group Theory")
+ (flags -w -deprecated -w -non-full-mutual -w -local-declaration))
+
+(include_subdirs qualified)
\ No newline at end of file

examples/sdk-demo/dune-project

-(lang dune 2.5)
+(lang dune 3.1)
 (using coq 0.2)

examples/sdk-demo/dune-workspace

-(lang dune 2.4)
-