patch 8.2.2142: memory leak when heredoc is not terminated

Problem:    Memory leak when heredoc is not terminated.
Solution:   Free heredoc_trimmed.

src/userfunc.c

@@ -3705,6 +3705,7 @@ errret_2:
 ret_free:
     ga_clear_strings(&argtypes);
     vim_free(skip_until);
+    vim_free(heredoc_trimmed);
     vim_free(line_to_free);
     vim_free(fudi.fd_newkey);
     if (name != name_arg)

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2142,
 /**/
     2141,
 /**/