[HACKERS] Inconsistent syntax for NumericOnly grammar production

I noticed that gram.y has

NumericOnly:           FCONST                              { $$ = makeFloat($1); }           | '-' FCONST
{                  $$ = makeFloat($2);                   doNegateFloat($$);               }           | SignedIconst
                 { $$ = makeInteger($1); }       ;
 

but

SignedIconst: Iconst                                { $$ = $1; }           | '+' Iconst                            { $$
=+ $2; }           | '-' Iconst                            { $$ = - $2; }       ;
 

The inconsistency here means that you can do, for example,

regression=# set random_page_cost = +4;
SET
regression=# set random_page_cost = 4.2;
SET

but not

regression=# set random_page_cost = +4.2;
ERROR:  syntax error at or near "4.2"
LINE 1: set random_page_cost = +4.2;                               ^

That's weird enough in itself, and the problem is about to get more
widespread because the partbound_datum production depends on NumericOnly.

Any objections to allowing "+ FCONST" here?  I'm inclined to
fix this and back-patch it as well.
        regards, tom lane