Change name from target client id to replaces client id

We had decided to change the name of FetchEvent.targetClientId to
.replacesClientId to clarify the meaning that this client is a to be replaced
client: w3c/ServiceWorker#1091 (comment).
Accordingly, this changes the reference to the request's target client id to
request's replaces client id.

Related issue: w3c/ServiceWorker#1245.

SW PR: w3c/ServiceWorker#1333.
Fetch PR: whatwg/fetch#774.

source

@@ -2832,7 +2832,7 @@ a.setAttribute('href', 'https://example.com/'); // change the content attribute
        <li><dfn data-x="concept-request-body" data-x-href="https://fetch.spec.whatwg.org/#concept-request-body">body</dfn></li>
        <li><dfn data-x="concept-request-client" data-x-href="https://fetch.spec.whatwg.org/#concept-request-client">client</dfn></li>
        <li><dfn data-x="concept-request-reserved-client" data-x-href="https://fetch.spec.whatwg.org/#concept-request-reserved-client">reserved client</dfn></li>
-       <li><dfn data-x="concept-request-target-client-id" data-x-href="https://fetch.spec.whatwg.org/#concept-request-target-client-id">target client id</dfn></li>
+       <li><dfn data-x="concept-request-target-client-id" data-x-href="https://fetch.spec.whatwg.org/#concept-request-replaces-client-id">replaces client id</dfn></li>
        <li><dfn data-x="concept-request-initiator" data-x-href="https://fetch.spec.whatwg.org/#concept-request-initiator">initiator</dfn></li>
        <li><dfn data-x="concept-request-destination" data-x-href="https://fetch.spec.whatwg.org/#concept-request-destination">destination</dfn></li>
        <li><dfn data-x="concept-potential-destination" data-x-href="https://fetch.spec.whatwg.org/#concept-potential-destination">potential destination</dfn></li>
@@ -81981,7 +81981,7 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
      data-x="concept-request-url">url</span>'s <span data-x="concept-url-scheme">scheme</span>
      is a <span>fetch scheme</span></dt>
      <dd><p>Run <span>process a navigate fetch</span> given <var>resource</var>, the <span>source
-     browsing context</span>, and <var>browsing context</var>, and <var>navigationType</var>.</p></dd>
+     browsing context</span>, and <var>browsingContext</var>, and <var>navigationType</var>.</p></dd>
 
      <dt>Otherwise, <var>resource</var> is a <span data-x="concept-request">request</span> whose
      <span data-x="concept-request-url">url</span>'s <span data-x="concept-url-scheme">scheme</span>
@@ -82008,7 +82008,7 @@ interface <dfn>Location</dfn> { // but see also <a href="#the-location-interface
    data-x="">navigate</code>", <span data-x="concept-request-credentials-mode">credentials
    mode</span> to "<code data-x="">include</code>", <span>use-URL-credentials flag</span>, <span
    data-x="concept-request-redirect-mode">redirect mode</span> to "<code data-x="">manual</code>",
-   and <span data-x="concept-request-target-client-id">target client id</span> to
+   and <span data-x="concept-request-replaces-client-id">replaces client id</span> to
    <var>browsingContext</var>'s <span>active document</span>'s <span>relevant settings
    object</span>'s <span data-x="concept-environment-id">id</span>.</p></li>