patch 8.2.3633: Vim9: line number of lambda is off by one

Problem:    Vim9: line number of lambda is off by one.
Solution:   Add one to the line number. (closes #9083)
diff --git a/src/userfunc.c b/src/userfunc.c
index 2f0637e..95d9c4a 100644
--- a/src/userfunc.c
+++ b/src/userfunc.c
@@ -1491,7 +1491,7 @@
 	fp->uf_flags = flags;
 	fp->uf_calls = 0;
 	fp->uf_script_ctx = current_sctx;
-	fp->uf_script_ctx.sc_lnum += SOURCING_LNUM - newlines.ga_len;
+	fp->uf_script_ctx.sc_lnum += SOURCING_LNUM - newlines.ga_len + 1;
 
 	function_using_block_scopes(fp, evalarg->eval_cstack);