vim-patch:9.0.1990: strange error number

Problem:  strange error number
Solution: change error number,
          add doc tag for E1507

closes: vim/vim#13270

ea746f9e86

Co-authored-by: Christ van Willegen <cvwillegen@gmail.com>

src/nvim/eval.lua

@@ -7572,6 +7572,14 @@ M.funcs = {
       	echo printf("%1$d at width %2$d is: %01$*2$.3$d", 1, 2)
       <	E1505: Invalid format specifier:
       	%1$d at width %2$d is: %01$*2$.3$d
+
+      					*E1507*
+      This internal error indicates that the logic to
+      parse a positional format error ran into a problem
+      that couldn't be otherwise reported. Please file a
+      bug against vim if you run into this, copying the
+      exact format string and parameters that were used.
+
     ]=],
     name = 'printf',
     params = { { 'fmt', 'any' }, { 'expr1', 'any' } },