Samples: use simple SSML examples, eg. <speak>Hello there.</speak>

samples/resources/hello.ssml

@@ -1,7 +1 @@
-<?xml version="1.0"?>
-  <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis"
-  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-  xsi:schemaLocation="http://www.w3.org/2001/10/synthesis
-  http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US">
-  Hello there.
-</speak>
+<speak>Hello there.</speak>

samples/synthesize.js

@@ -58,7 +58,7 @@ function synthesizeSsml(ssml, outputFile) {
   /**
    * TODO(developer): Uncomment the following lines before running the sample.
    */
-  // const ssml = 'SSML to synthesize, eg. <?xml version="1.0"?><speak...';
+  // const ssml = '<speak>Hello there.</speak>';
   // const outputFile = 'Local path to save audio file to, e.g. output.mp3';
 
   const request = {
@@ -177,7 +177,7 @@ require(`yargs`) // eslint-disable-line
     },
   })
   .example(`node $0 text "hello" -o hello.mp3`)
-  .example(`node $0 ssml "<?xml..." -o hello.mp3`)
+  .example(`node $0 ssml "<speak>Hello there.</speak>" -o hello.mp3`)
   .example(`node $0 text-file filename.txt -o output.mp3`)
   .example(`node $0 ssml-file filename.ssml -o output.mp3`)
   .wrap(120)

samples/system-test/synthesize.test.js

@@ -23,13 +23,7 @@ const tools = require(`@google-cloud/nodejs-repo-tools`);
 const cmd = `node synthesize.js`;
 const cwd = path.join(__dirname, `..`);
 const text = `Hello there.`;
-const ssml = `<?xml version="1.0"?>
-<speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis"
-xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-xsi:schemaLocation="http://www.w3.org/2001/10/synthesis
-http://www.w3.org/TR/speech-synthesis/synthesis.xsd" xml:lang="en-US">
-Hello there.
-</speak>`;
+const ssml = `<speak>Hello there.</speak>`;
 const outputFile = `test-output.mp3`;
 const files = [`hello.txt`, `hello.ssml`].map(name => {
   return {