modify terms and definitions to align with Ecma style (#111)

Author: gesa

index.bs

@@ -75,16 +75,19 @@ The following documents are referred to in the text in such a way that some or a
 Terms and definitions {#terminology}
 ====================================
 
+For the purposes of this document, the terms and definitions given in  ECMA-262, Compression Standard, Console Standard, DOM Standard, Encoding Standard, Fetch Standard, File API, High-Resolution Time, HTML Standard, Streams Standard, URL Standard, URL Pattern Standard, WebAssembly JavaScript Interface, WebAssembly Web API, W3C Web Cryptography Level 2, and the following apply. Externally-defined terms are mapped to source in Annex A.
+
 <dfn>Web Platform</dfn> {#term-web-platform}
 --------------------------------------------
 
-The Web Platform is the combination of technology standards defined by organizations such as the W3C, the WHATWG, and others as implemented by Web Browsers.
+the combination of technology standards defined by organizations such as the W3C, the WHATWG, and others as implemented by Web Browsers
 
 <dfn>Web-interoperable Runtime</dfn> {#term-web-interoperable-runtime}
 ----------------------------------------------------------------------
 
-Any ECMAScript-based runtime environment that implements this Standard. Web Browsers are Web-interoperable Runtimes.
+ECMAScript-based runtime environment that implements this Standard
 
+Note: Web Browsers are Web-interoperable Runtimes.<br>
 The term "Web-interoperable Runtime" is intentionally broad. The primary focus of this Standard is web server runtimes.
 
 Common API Index {#api-index}