[web-api] Update media-type registration for review.

See #573.

document/web-api/index.bs

@@ -253,17 +253,27 @@ application/wasm
 <dt>Encoding Considerations:</dt>
  <dd>binary</dd>
 <dt>Security Considerations:</dt>
- <dd>See see WebAssembly Core Security Considerations<br/>
- https://www.w3.org/TR/wasm-core/#security-considerations%E2%91%A0</dd>
+ <dd>
+  <p>WebAssembly is a standard, a safe, portable, low-level code format. The
+  security considerations associated with executing WebAssembly code are
+  described in https://www.w3.org/TR/wasm-core/#security-considerations.</p>
+  <p>The WebAssembly format includes no integrity or privacy protection. If
+  such protection is needed it must be provided externally, e.g., through
+  the use of HTTPS.</p>
+ </dd>
 <dt>Interoperability Considerations:</dt>
- <dd>See see WebAssembly Core Conformance<br/>
+ <dd>See WebAssembly Core Conformance<br/>
  https://www.w3.org/TR/wasm-core/#conformance</dd>
 <dt>Published specification:</dt>
- https://www.w3.org/TR/wasm-core-1/
+ <dd>https://www.w3.org/TR/wasm-core-1/
  https://www.w3.org/TR/wasm-js-api-1/
- https://www.w3.org/TR/wasm-web-api-1/
+ https://www.w3.org/TR/wasm-web-api-1/</dd>
 <dt>Application Usage:</dt>
- <dd>The application/wasm media type is already in use as the type used to describe WebAssembly files when sent over HTTP to be executed by browsers, which is a common scenario. Additionally, several WebAssembly runtimes that take advantage of the safety and portability while targeting efficient execution and compact representation.</dd>
+ <dd>The application/wasm media type is intended for use as the type used to
+ describe WebAssembly files when sent over HTTP to be executed by browsers,
+ which is a common scenario. Additionally, the type is used by several
+ WebAssembly runtimes that take advantage of the safety and portability
+ while targeting efficient execution and compact representation.</dd>
 <dt>Fragment Identifier Considerations:</dt>
  <dd>None</dd>
 <dt>Restrictions on usage:</dt>