Rename tokens, and tidy up branch after review by Eli Z.

Rename tokens, and tidy up branch after review by Eli Z.

New defun position-symbol which creates a symbol with position.

* src/lisp.h, src/alloc.c, src/data.c, src/fns.c, src/lread.c, src/print.c:
Substitute tokens as follows:
build_located_symbol -> build_symbol_with_pos.
lisp_h_LOCATED_SYMBOL_P -> lisp_h_SYMBOL_WITH_POS_P.
lisp_h_ONLY_SYMBOL_P -> lisp_h_BARE_SYMBOL_P.
lisp_h_XLOCATED_SYMBOL -> lisp_h_XSYMBOL_WITH_POS.
lisp_h_XONLY_SYMBOL -> lisp_h_XBARE_SYMBOL.
Lisp_Located_Symbol -> Lisp_Symbol_With_Pos.

located-symbol-loc -> symbol-with-pos-pos.
LOCATED_SYMBOL_LOC -> SYMBOL_WITH_POS_POS.
located-symbol-p -> symbol-with-pos-p.
LOCATED_SYMBOL_P -> SYMBOL_WITH_POS_P.
located-symbols-enabled -> symbols-with-pos-enabled.

located-symbol-sym -> symbol-with-pos-sym.
LOCATED_SYMBOL_SYM -> SYMBOL_WITH_POS_SYM.
.loc -> .pos in struct Lisp_Symbol_With_Pos.
only-symbol-p -> bare-symbol-p.
ONLY_SYMBOL_P -> BARE_SYMBOL_P.

PVEC_LOCATED_SYMBOL -> PVEC_SYMBOL_WITH_POS.
read-locating-symbols -> read-positioning-symbols.
XLOCATED_SYMBOL -> XSYMBOL_WITH_POS.
XONLY_SYMBOL -> XBARE_SYMBOL.

* src/lisp.h (Lisp_Object, vectorlike_header, pvec_type, More_Lisp_Bits):
Restore to their previous positions in the file.
(SYMBOLP, XSYMBOL, make_lisp_symbol, builtin_lisp_symbol, CHECK_SYMBOL): Move
to after More_Lisp_Bits so that the source will compile.
(PSEUDOVECTORP): Invoke the (new) macro lisp_h_PSUEDOVECTORP in place of open
coding.

* src/data.c (position-symbol): New defun.