Editorial: Add intro prose for ES2019.

spec.html

@@ -83,15 +83,16 @@ <h1>Introduction</h1>
   <p>Focused development of the sixth edition started in 2009, as the fifth edition was being prepared for publication. However, this was preceded by significant experimentation and language enhancement design efforts dating to the publication of the third edition in 1999. In a very real sense, the completion of the sixth edition is the culmination of a fifteen year effort. The goals for this addition included providing better support for large applications, library creation, and for use of ECMAScript as a compilation target for other languages. Some of its major enhancements included modules, class declarations, lexical block scoping, iterators and generators, promises for asynchronous programming, destructuring patterns, and proper tail calls. The ECMAScript library of built-ins was expanded to support additional data abstractions including maps, sets, and arrays of binary numeric values as well as additional support for Unicode supplemental characters in strings and regular expressions. The built-ins were also made extensible via subclassing. The sixth edition provides the foundation for regular, incremental language and library enhancements. The sixth edition was adopted by the General Assembly of June 2015.</p>
   <p>ECMAScript 2016 was the first ECMAScript edition released under Ecma TC39's new yearly release cadence and open development process. A plain-text source document was built from the ECMAScript 2015 source document to serve as the base for further development entirely on GitHub. Over the year of this standard's development, hundreds of pull requests and issues were filed representing thousands of bug fixes, editorial fixes and other improvements. Additionally, numerous software tools were developed to aid in this effort including Ecmarkup, Ecmarkdown, and Grammarkdown. ES2016 also included support for a new exponentiation operator and adds a new method to Array.prototype called `includes`.</p>
   <p>ECMAScript 2017 introduced Async Functions, Shared Memory, and Atomics along with smaller language and library enhancements, bug fixes, and editorial updates. Async functions improve the asynchronous programming experience by providing syntax for promise-returning functions. Shared Memory and Atomics introduce a new memory model that allows multi-agent programs to communicate using atomic operations that ensure a well-defined execution order even on parallel CPUs. This specification also includes new static methods on Object: `Object.values`, `Object.entries`, and `Object.getOwnPropertyDescriptors`.</p>
-  <p>This specification, the 9<sup>th</sup> edition, introduces support for asynchronous iteration via the AsyncIterator protocol and async generators. This specification also includes four new regular expression features: the dotAll flag, named capture groups, Unicode property escapes, and look-behind assertions. It also includes rest parameter and spread operator support for object properties. There have also been many minor updates, editorial and normative, with many contributions from our awesome community.</p>
+  <p>ECMAScript 2018 introduced support for asynchronous iteration via the AsyncIterator protocol and async generators. It also included four new regular expression features: the dotAll flag, named capture groups, Unicode property escapes, and look-behind assertions. Lastly it included rest parameter and spread operator support for object properties.</p>
+  <p>This specification, the 10<sup>th</sup> edition, introduces a few new built-in functions: `flat` and `flatMap` on `Array.prototype` for flattening arrays, `Object.fromEntries` for directly turning the return value of `Object.entries` into a new Object, and `trimStart` and `trimEnd` on `String.prototype` as better-named alternatives to the widely implemented but non-standard `String.prototype.trimLeft` and `trimRight` built-ins. In addition, this specification includes a few minor updates to syntax and semantics. Updated syntax includes optional catch binding parameters and allowing U+2028 (LINE SEPARATOR) and U+2029 (PARAGRAPH SEPARATOR) in string literals to align with JSON. Other updates include requiring that `Array.prototype.sort` be a stable sort, requiring that JSON.stringify return well-formed UTF-8 regardless of input, and clarifying `Function.prototype.toString` by requiring that it either return the corresponding original source text or a standard placeholder.</p>
   <p>Dozens of individuals representing many organizations have made very significant contributions within Ecma TC39 to the development of this edition and to the prior editions. In addition, a vibrant community has emerged supporting TC39's ECMAScript efforts. This community has reviewed numerous drafts, filed thousands of bug reports, performed implementation experiments, contributed test suites, and educated the world-wide developer community about ECMAScript. Unfortunately, it is impossible to identify and acknowledge every person and organization who has contributed to this effort.</p>
   <p>
     Allen Wirfs-Brock<br>
-    ECMA-262, 6<sup>th</sup> Edition Project Editor
+    ECMA-262, Project Editor, 6<sup>th</sup> Edition
   </p>
   <p>
     Brian Terlson<br>
-    ECMA-262, 7<sup>th</sup> Edition Project Editor
+    ECMA-262, Project Editor, 7<sup>th</sup> through 10<sup>th</sup> Editions
   </p>
 </emu-intro>