Add a few new tests for leading-whitespace and duplicate-variant

Author: eemeli

test/tests/data-model-errors.json

@@ -180,6 +180,10 @@
           "type": "duplicate-variant"
         }
       ]
+    },
+    {
+      "src": ".match {star :string} |*| {{Literal star}} * {{The default}}",
+      "exp": "The default"
     }
   ]
 }

test/tests/syntax.json

@@ -196,6 +196,18 @@
       "src": ".local $x = {a}{{}}",
       "exp": ""
     },
+    {
+      "description": "input-declaration-like content in complex-message",
+      "src": "{{.input {$x}}}",
+      "params": [{ "name": "x", "value": "X" }],
+      "exp": ".input X"
+    },
+    {
+      "description": "local-declaration-like content in complex-message with leading whitespace",
+      "src": "{{ .local $x = {$y}}}",
+      "params": [{ "name": "y", "value": "Y" }],
+      "exp": " .local $x = Y"
+    },
     {
       "description": "... matcher -> match-statement [s] variant -> match 1*([s] selector) variant -> match selector selector variant -> match selector selector variant key s key quoted-pattern",
       "src": ".match{a :f}{b :f}a b{{}}* *{{}}",