patch 8.2.4071: Vim9: no detection of return in try/endtry

Problem:    Vim9: no detection of return in try/endtry. (Dominique Pellé)
Solution:   Check if any of the blocks inside try/endtry did not end in
            return.
diff --git a/src/vim9cmds.c b/src/vim9cmds.c
index 3372ad4..5beeab8 100644
--- a/src/vim9cmds.c
+++ b/src/vim9cmds.c
@@ -1343,6 +1343,8 @@
 	emsg(_(e_catch_unreachable_after_catch_all));
 	return NULL;
     }
+    if (!cctx->ctx_had_return)
+	scope->se_u.se_try.ts_no_return = TRUE;
 
     if (cctx->ctx_skip != SKIP_YES)
     {
@@ -1498,6 +1500,7 @@
 	    isn->isn_arg.jump.jump_where = this_instr;
 	    scope->se_u.se_try.ts_catch_label = 0;
 	}
+	scope->se_u.se_try.ts_has_finally = TRUE;
 	if (generate_instr(cctx, ISN_FINALLY) == NULL)
 	    return NULL;
     }
@@ -1567,6 +1570,14 @@
 	}
     }
 
+    // If there is a finally clause that ends in return then we will return.
+    // If one of the blocks didn't end in "return" or we did not catch all
+    // exceptions reset the had_return flag.
+    if (!(scope->se_u.se_try.ts_has_finally && cctx->ctx_had_return)
+	    && (scope->se_u.se_try.ts_no_return
+		|| !scope->se_u.se_try.ts_caught_all))
+	cctx->ctx_had_return = FALSE;
+
     compile_endblock(cctx);
 
     if (cctx->ctx_skip != SKIP_YES)