Fix a typo (#1459)

Author: jungkees

docs/index.bs

@@ -287,7 +287,7 @@ spec: webappsec-referrer-policy; urlPrefix: https://w3c.github.io/webappsec-refe
 
       Note: For an initial [=navigate|navigation=] with [=replacement enabled=], the initial [=window client=] that was [created](https://html.spec.whatwg.org/#set-up-a-window-environment-settings-object) when the [=/browsing context=] was [created](https://html.spec.whatwg.org/#creating-a-new-browsing-context) is reused, but the [=active service worker=] is determined by the same behavior as above.
 
-      Note: [Sandboxed](https://html.spec.whatwg.org/#attr-iframe-sandbox) [=iframes=] without the sandboxing directives, `allow-same-origin` and `allow-scripts`, result in having the [=active service worker=] value of null as their [=/origin=] is an [=opaque origin=]..
+      Note: [Sandboxed](https://html.spec.whatwg.org/#attr-iframe-sandbox) [=iframes=] without the sandboxing directives, `allow-same-origin` and `allow-scripts`, result in having the [=active service worker=] value of null as their [=/origin=] is an [=opaque origin=].
     </section>
 
     <section>

docs/v1/index.bs

@@ -270,7 +270,7 @@ spec: webappsec-referrer-policy; urlPrefix: https://w3c.github.io/webappsec-refe
 
       Note: For an initial [=navigate|navigation=] with [=replacement enabled=], the initial [=window client=] that was [created](https://html.spec.whatwg.org/#set-up-a-window-environment-settings-object) when the [=/browsing context=] was [created](https://html.spec.whatwg.org/#creating-a-new-browsing-context) is reused, but the [=active service worker=] is determined by the same behavior as above.
 
-      Note: [Sandboxed](https://html.spec.whatwg.org/#attr-iframe-sandbox) [=iframes=] without the sandboxing directives, `allow-same-origin` and `allow-scripts`, result in having the [=active service worker=] value of null as their [=/origin=] is an [=opaque origin=]..
+      Note: [Sandboxed](https://html.spec.whatwg.org/#attr-iframe-sandbox) [=iframes=] without the sandboxing directives, `allow-same-origin` and `allow-scripts`, result in having the [=active service worker=] value of null as their [=/origin=] is an [=opaque origin=].
     </section>
 
     <section>