patch 8.2.3352: Vim9: error for nested :enddef has wrong line number

Problem:    Vim9: error for nested :enddef has wrong line number.
Solution:   Compute the line number.
diff --git a/src/userfunc.c b/src/userfunc.c
index 7a7617f..86a2bec 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -822,6 +822,8 @@
 		    else if (*p != NUL && *p != (vim9_function ? '#' : '"')
 					   && (vim9_function || p_verbose > 0))
 		    {
+			SOURCING_LNUM = sourcing_lnum_top
+							+ newlines->ga_len + 1;
 			if (eap->cmdidx == CMD_def)
 			    semsg(_(e_text_found_after_enddef_str), p);
 			else