d: remove unnecessary methods from the Lexer interface

The complete symbol approach in yylex removes the need for the methods
semanticVal, startPos and endPos, which were used when the values were
reported separately.

* data/skeletons/lalr1.d: Here.
* doc/bison.texi: Remove sections about the three methods.
* examples/d/calc/calc.y, examples/d/simple/calc.y: Remove the unused methods.
* tests/calc.at, tests/d.at, tests/scanner.at: Test it.

doc/bison.texi

@@ -14016,16 +14016,6 @@ Return the next token. The return value is of type @code{Symbol}, which
 binds together the kind, the semantic value and the location.
 @end deftypemethod
 
-@deftypemethod {Lexer} {Position} getStartPos()
-@deftypemethodx {Lexer} {Position} getEndPos()
-Return respectively the first position of the last token that @code{yylex}
-returned, and the first position beyond it.  These methods are not needed
-unless location tracking is active.
-
-They should return new objects for each call, to avoid that all the symbol
-share the same Position boundaries.
-@end deftypemethod
-
 @deftypemethod {Lexer} {void} reportSyntaxError(@code{YYParser.Context} @var{ctx})
 If you invoke @samp{%define parse.error custom} (@pxref{Bison
 Declarations}), then the parser no longer passes syntax error messages to