support whisper say verb instructions

specs.json

@@ -213,6 +213,7 @@
     "properties": {
       "id": "string",
       "text": "string|array",
+      "instructions": "string",
       "stream": "boolean",
       "loop": "number|string",
       "synthesizer": "#synthesizer",

test/jambonz-verb-test.js

@@ -221,6 +221,10 @@ test("validate correct verbs", async (t) => {
           "fallbackVoice": "voice"
         }
       },
+      "say": {
+        "text": "To speak to Sales press 1 or say Sales.  To speak to customer support press 2 or say Support",
+        "instructions": "Voice: High-energy, upbeat, and encouraging, projecting enthusiasm and motivation."
+      },
       "say": {
         "text": "To speak to Sales press 1 or say Sales.  To speak to customer support press 2 or say Support",
         "synthesizer": {