Remove deprecated RGBASM features (#1215)

- Escaped commas "\," inside strings
- `name: MACRO` syntax
- `__FILE__` and `__LINE__`
- `-H/--nop-after-halt` and `-l/--auto-ldh` on by default

man/rgbasm.5

@@ -1249,16 +1249,6 @@ The example above defines
 as a new macro.
 String constants are not expanded within the name of the macro.
 .Pp
-(Using the
-.Em deprecated
-older syntax
-.Ql MyMacro: MACRO
-instead of
-.Ql MACRO MyMacro ,
-with a single colon
-.Ql \&:
-following the macro's name, string constants may be expanded for the name.)
-.Pp
 Macros can't be exported or imported.
 .Pp
 Plainly nesting macro definitions is not allowed, but this can be worked around using