Revert "JSON completion provider doesn't work without triggering characters."

This reverts commit d5f9985edbe088c0ff645e9cf8aeac18976991f9.

test/playground.generated/extending-language-services-completion-provider-example.html

@@ -63,7 +63,6 @@ function createDependencyProposals() {
 
 
 monaco.languages.registerCompletionItemProvider('json', {
-    triggerCharacters: ['\"'],
     provideCompletionItems: function(model, position) {
         // find out if we are completing a property in the 'dependencies' object.
         var textUntilPosition = model.getValueInRange({startLineNumber: 1, startColumn: 1, endLineNumber: position.lineNumber, endColumn: position.column});

website/playground/new-samples/extending-language-services/completion-provider-example/sample.js

@@ -25,7 +25,6 @@ function createDependencyProposals() {
 
 
 monaco.languages.registerCompletionItemProvider('json', {
-    triggerCharacters: ['\"'],
     provideCompletionItems: function(model, position) {
         // find out if we are completing a property in the 'dependencies' object.
         var textUntilPosition = model.getValueInRange({startLineNumber: 1, startColumn: 1, endLineNumber: position.lineNumber, endColumn: position.column});