Drop toJSON as reserved identifier

This allows whatwg/url#137 to move on.

index.bs

@@ -559,7 +559,7 @@ is simply that token.
 
 The [=identifier=] of any of the abovementioned
 IDL constructs must not be “constructor”,
-“toString”, “toJSON”,
+“toString”,
 or begin with a <span class="char">U+005F LOW LINE ("_")</span> character.  These
 are known as <dfn id="dfn-reserved-identifier" export>reserved identifiers</dfn>.
 

index.html

@@ -1177,7 +1177,7 @@
 		}
 	}
 </style>
-  <meta content="Bikeshed version 009836c46217067220542eccc715a300175723d6" name="generator">
+  <meta content="Bikeshed version 6ef2009a74468c39cdee1058d2c325259bdcb4fa" name="generator">
 <style>
         pre.set {
           font-size: 80%;
@@ -1567,7 +1567,7 @@
   <div class="head">
    <p data-fill-with="logo"><a class="logo" href="http://www.w3.org/"> <img alt="W3C" height="48" src="https://www.w3.org/StyleSheets/TR/2016/logos/W3C" width="72"> </a> </p>
    <h1 class="p-name no-ref" id="title">Web IDL</h1>
-   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">Editor’s Draft, <time class="dt-updated" datetime="2017-01-31">31 January 2017</time></span></h2>
+   <h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">Editor’s Draft, <time class="dt-updated" datetime="2017-02-02">2 February 2017</time></span></h2>
    <div data-fill-with="spec-metadata">
     <dl>
      <dt>This version:
@@ -2110,7 +2110,7 @@ <h3 class="heading settled" data-level="2.1" id="idl-names"><span class="secno">
 is simply that token.</p>
    <p>The <a data-link-type="dfn" href="#dfn-identifier" id="ref-for-dfn-identifier-4">identifier</a> of any of the abovementioned
 IDL constructs must not be “constructor”,
-“toString”, “toJSON”,
+“toString”,
 or begin with a <span class="char">U+005F LOW LINE ("_")</span> character.  These
 are known as <dfn class="dfn-paneled" data-dfn-type="dfn" data-export="" id="dfn-reserved-identifier">reserved identifiers</dfn>.</p>
    <p class="note" role="note"><span>Note:</span> Further restrictions on identifier names for particular constructs may be made