Don't use @w around @xref in ede.texi

Don't use @w around @xref in ede.texi

Texinfo 7 warns about this now.

* doc/misc/ede.texi (ede-project-placeholder, ede-project,
ede-cpp-root-project, ede-simple-project,ede-simple-base-project,
ede-proj-project, project-am-makefile, ede-step-project, ede-target,
ede-proj-target, ede-proj-target-makefile,
semantic-ede-proj-target-grammar, ede-proj-target-makefile-objectcode,
ede-proj-target-makefile-archive, ede-proj-target-makefile-program,
ede-proj-target-makefile-shared-object, ede-proj-target-elisp,
ede-proj-target-elisp-autoloads,
ede-proj-target-makefile-miscelaneous, ede-proj-target-makefile-info,
ede-proj-target-scheme, project-am-target, project-am-objectcode,
project-am-program, project-am-header-noinst, project-am-header-inst,
project-am-lisp, project-am-texinfo, project-am-man,
ede-compilation-program, ede-compiler, ede-object-compiler,
ede-linker): Remove @w around @xref.