Correct a variety of documentation issues (#34786)

Fix some warnings in documentation as well as some faulty documentation
introduced in #34776.

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/script/dom/intersectionobserver.rs

@@ -89,7 +89,7 @@ impl IntersectionObserverMethods<crate::DomTypeHolder> for IntersectionObserver
     /// > is a ratio of intersection area to bounding box area of an observed target.
     /// > Notifications for a target are generated when any of the thresholds are crossed
     /// > for that target. If no options.threshold was provided to the IntersectionObserver
-    /// > constructor, or the sequence is empty, the value of this attribute will be [0].
+    /// > constructor, or the sequence is empty, the value of this attribute will be `[0]`.
     ///
     /// <https://w3c.github.io/IntersectionObserver/#dom-intersectionobserver-thresholds>
     fn Thresholds(&self, _context: JSContext, _retval: MutableHandleValue) {}

components/script/dom/readablestreamdefaultreader.rs

@@ -104,7 +104,7 @@ struct ClosedPromiseRejectionHandler {
 
 impl Callback for ClosedPromiseRejectionHandler {
     /// Continuation of <https://streams.spec.whatwg.org/#readable-stream-default-controller-call-pull-if-needed>
-    /// Upon rejection of reader.[[closedPromise]] with reason r,
+    /// Upon rejection of `reader.closedPromise` with reason `r``,
     fn callback(&self, _cx: SafeJSContext, v: SafeHandleValue, _realm: InRealm, _can_gc: CanGc) {
         let branch_1_controller = &self.branch_1_controller;
         let branch_2_controller = &self.branch_2_controller;