optimise internal calls to f-string parsing functions

Cython/Compiler/Parsing.pxd

@@ -68,6 +68,10 @@ cdef p_opt_string_literal(PyrexScanner s, required_type=*)
 cdef bint check_for_non_ascii_characters(unicode string)
 @cython.locals(systr=unicode, is_python3_source=bint, is_raw=bint)
 cdef p_string_literal(PyrexScanner s, kind_override=*)
+@cython.locals(i=Py_ssize_t, size=Py_ssize_t)
+cdef list p_f_string(PyrexScanner s, unicode unicode_value, pos)
+@cython.locals(i=Py_ssize_t, size=Py_ssize_t)
+cdef tuple p_f_string_expr(PyrexScanner s, unicode unicode_value, pos, Py_ssize_t starting_index)
 cdef p_list_maker(PyrexScanner s)
 cdef p_comp_iter(PyrexScanner s, body)
 cdef p_comp_for(PyrexScanner s, body)