Apply suggestions from HTML editor code review

Co-authored-by: Domenic Denicola <d@domenic.me>

research/src/pages/popup/popup.proposal.mdx

@@ -161,8 +161,7 @@ The `show()` method renders the `popup` element, such that the user can interact
 ```
 
 The show() method steps are to run the [showing a `popup` element steps](#showing-popup-steps) with
-[this](https://heycam.github.io/webidl/#this) with _candidate subject_ set to the new candidate
-`popup` element to be shown.
+[this](https://heycam.github.io/webidl/#this).
 
 ### The `popup` attribute
 
@@ -211,8 +210,7 @@ steps:
 2. Get the _subject_'s _open state_.
 3. If _subject_'s _open state_ is `true`, run
    [hiding a `popup` element steps](#hiding-current-popups).
-4. Otherwise, run [showing a `popup` element steps](#showing-popup-steps), with _candidate subject_
-   set to _subject_ and _invoker_ set to the current element _invoker_.
+4. Otherwise, run [showing a `popup` element steps](#showing-popup-steps) with _subject_ and _invoker_.
 
 <p class="question">
   Should we have a way to suppress these steps upon focus, so that the author can enable the popup
@@ -227,22 +225,19 @@ The **showing a `popup` element steps**, given a popup element _candidate subjec
 element _invoker_, and an optional element _anchor element_, are:
 
 1. Run the [hiding currently-shown `popup` elements steps](#hiding-current-popups), with the
-   _candidate subject_, optional element _invoker_, and optional element _anchor element_.
+   _candidate subject_, _invoker_ if it was given, and _anchor element_ if it was given.
 2. Add the _candidate subject_ to _candidate subject_'s
    [node document](https://dom.spec.whatwg.org/#concept-node-document)'s [popup stack](#popup-stack).
 3. Set the `open` IDL attribute on the _candidate subject_ to `true`.
 4. Set the _candidate subject_'s _open state_ to `true`.
 5. If the `popup` element was shown as a result of a user interaction with an `invoker`, internally
    set the _candidate subject_'s _invoker_ to a pointer to the `invoker` element.
-6. Run [get the focusable area
-   steps](https://html.spec.whatwg.org/multipage/interaction.html#get-the-focusable-area) with
-   _focus target_ set to the _candidate subject_.
-7. Run [focusing steps](https://html.spec.whatwg.org/multipage/interaction.html#focusing=steps)
-   with _new focus target_ set to the returned node from [get the focusable area
-   steps](https://html.spec.whatwg.org/multipage/interaction.html#get-the-focusable-area).
+6. Let _focusableArea_ be the result of [getting the focusable area
+   steps](https://html.spec.whatwg.org/multipage/interaction.html#get-the-focusable-area) given _candidate subject_.
+7. Run the [focusing steps](https://html.spec.whatwg.org/multipage/interaction.html#focusing-steps) given _focusableArea_.
 
 <p class="note">
-  Without the precense of the autofocus or delegatefocus attribute, focus remains on the active
+  Without the presence of the autofocus or delegatefocus attribute, focus remains on the active
   element. This behavior is to enable scenarios where the popup is used in a composite control. For
   example, a combobox where the user expects their focus to stay in the text input instead of moving
   automatically to the listbox popup as and when it appears.
@@ -283,7 +278,7 @@ shown, focus should move to the descendent of the `popup` element where `autofoc
 
 The `delegatesfocus` content attribute is a
 [boolean attribute](https://html.spec.whatwg.org/multipage/common-microsyntaxes.html#boolean-attribute).
-When specified, it indicates that when the `popup` element is shown, focus should move to the first
+When specified, it indicates that when the `popup` element is shown, focus will move to the first
 focusable descendent of the `popup` element.
 
 **Example:**
@@ -317,7 +312,7 @@ relationship. When specified, the attribute's value must be the ID of an element
 </popup>
 ```
 
-The target of the `anchor` attribute participates in determining whether a candiate _popup_ element
+The target of the `anchor` attribute participates in determining whether a candidate `popup` element
 is "nested" in a currently-shown `popup`; refer to <a href="#hiding-current-popups">hiding
 currently-shown <code>popup</code> elements steps</a>.