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.

src/testdir/test_vim9_script.vim

@@ -667,7 +667,6 @@ def Test_try_catch_throw()
     finally
       return 6
     endtry
-    return -1
   enddef
   assert_equal(6, ReturnInFinally())
 
@@ -708,6 +707,64 @@ def Test_try_catch_throw()
   CheckDefAndScriptSuccess(lines)
 enddef
 
+def Test_try_ends_in_return()
+  var lines =<< trim END
+      vim9script
+      def Foo(): string
+        try
+          return 'foo'
+        catch
+          return 'caught'
+        endtry
+      enddef
+      assert_equal('foo', Foo())
+  END
+  CheckScriptSuccess(lines)
+
+  lines =<< trim END
+      vim9script
+      def Foo(): string
+        try
+          return 'foo'
+        catch
+          return 'caught'
+        endtry
+        echo 'notreached'
+      enddef
+      assert_equal('foo', Foo())
+  END
+  CheckScriptFailure(lines, 'E1095:')
+
+  lines =<< trim END
+      vim9script
+      def Foo(): string
+        try
+          return 'foo'
+        catch /x/
+          return 'caught'
+        endtry
+      enddef
+      assert_equal('foo', Foo())
+  END
+  CheckScriptFailure(lines, 'E1027:')
+
+  lines =<< trim END
+      vim9script
+      def Foo(): string
+        try
+          echo 'foo'
+        catch
+          echo 'caught'
+        finally
+          return 'done'
+        endtry
+      enddef
+      assert_equal('done', Foo())
+  END
+  CheckScriptSuccess(lines)
+
+enddef
+
 def Test_try_in_catch()
   var lines =<< trim END
       vim9script