Store function documentations in a hash table.

Store function documentations in a hash table.

	* src/pdumper.c (dump_subr): Update Lisp_Subr hash.
	(dump_subr): Update for new compilation unit layout.
	(dump_vectorlike): Update pvec_type hash.

	* src/lisp.h (struct Lisp_Subr): Remove 'native_doc' index.
	(DEFUN): Update macro for new compilation unit
	layout.

	* src/doc.c (Fdocumentation): Update for new compilation unit
	layout.

	* src/comp.h (struct Lisp_Native_Comp_Unit):
	Add 'data_fdoc_h' field.

	* src/comp.c (TEXT_FDOC_SYM): New macro.
	(emit_ctxt_code): Emit function documentations.
	(load_comp_unit): Load function documentation.
	(Fcomp__register_subr): Rename parameter.
	(Fcomp__register_subr): Update for new compilation unit
	layout.

	* src/alloc.c (mark_object): Update for new compilation unit
	layout.
	(syms_of_alloc): Likewise.

	* lisp/emacs-lisp/comp.el (comp-ctxt): Add doc-index-h slot.
	(comp-emit-for-top-level): Emit doc index as 'comp--register-subr'
	doc parameter.