Fix grammar in id section (#1102)

index.html

@@ -890,7 +890,7 @@ <h3>
         </ol>
         <aside class="example" title="Resulting ids">
           <p>
-            Below table shows some example `id`s resulting from the [=process
+            The table below shows some example `id`s resulting from the [=process
             the `id` member=] steps.
           </p>
           <table class="data">
@@ -1008,9 +1008,9 @@ <h3>
           <p>
             Since [=manifest/id=] is resolved against [=manifest/start_url=]'s
             [=URL/origin=], providing "../foo", "foo", "/foo", "./foo" all
-            resolves to the same [=identifier=]. It is As such, best practice
+            resolves to the same [=identifier=]. As such, best practice
             is to use a leading "/" to be explicit that the id is a
-            root-relative url path. Also, standard encoding/decoding rules are
+            root-relative URL path. Also, standard encoding/decoding rules
             apply to the id processing algorithm, as per the [[[URL]]].
           </p>
         </aside>