[css-transitions-2] Fix almost all bikeshed warnings.

This fixes all bikeshed warnings except for:
WARNING: This specification has neither a 'Security Considerations' nor a 'Privacy Considerations' section. Please consider adding both, see https://w3ctag.github.io/security-questionnaire/.

Note that this changes one (relatively recently added) ID for a heading
from #defining-before-change-style-the-starting-style-rule
to #defining-before-change-style.

Author: dbaron

css-transitions-2/Overview.bs

@@ -50,8 +50,7 @@ spec:web-animations-1; type:dfn;
     text:current time; for:animation
     text:current iteration
     text:fill mode
-    text:idle
-    text:idle play state
+    text:idle; for:play state
     text:iteration duration
     text:iteration start
     text:pending pause task
@@ -77,7 +76,7 @@ and backport the following paragraph.
 
 Although the 'transition-property' may specify shorthand properties and the
 ''all'' keyword, individual transitions are generated for each longhand
-sub-property that is transitionable. The <dfn>expanded transition property
+sub-property that is [=transitionable=]. The <dfn>expanded transition property
 name</dfn> of a transition is the name of the longhand sub-property for which
 the transition was generated (e.g. 'border-left-width').
 
@@ -86,7 +85,7 @@ once it is ported from Level 1.
 
 In CSS Transitions Level 2, when comparing the [=before-change style=] and
 [=after-change style=] for a given property, the property values are
-[=transitionable=] if:
+<dfn>transitionable</dfn> if:
 <ol>
  <li>They have an [=animation type=] that is neither [=not animatable=] nor
  [=discrete=], or</li>
@@ -199,7 +198,7 @@ Each time a new transition is generated, the current value of the (already
 incremented) <a>current transition generation</a> is stored as the
 transition's <dfn>transition generation</dfn>.
 
-## Defining [=before-change style=]: the ''@starting-style'' rule
+## Defining [=before-change style=]: the ''@starting-style'' rule ## {#defining-before-change-style}
 
 In Level 1 of this specification, transitions can only start during a
 [=style change event=] for elements which have a defined [=before-change style=]
@@ -307,7 +306,7 @@ Global, name-defining at-rules such as ''@keyframes'', ''@font-face'', and
 ''@layer'' are allowed inside ''@starting-style'', and when present behave as
 if they were outside of ''@starting-style''.
 
-### The <code>CSSStartingStyleRule</code> interface
+### The <code>CSSStartingStyleRule</code> interface ### {#the-cssstartingstylerule-interface}
 
 The {{CSSStartingStyleRule}} interface represents a ''@starting-style'' rule.
 
@@ -365,15 +364,15 @@ are sorted in composite order (first to last) as follows:
 Transitions generated using the markup defined in this specification are
 <em>not</em> added to the <a>global animation list</a> when they are created.
 Instead, these animations are appended to the <a>global animation list</a> at
-the first moment when they transition out of the <a>idle play state</a> after
+the first moment when they transition out of the [=play state/idle|idle play state=] after
 being disassociated from their <a>owning element</a>.
 Transitions that have been disassociated from their <a>owning element</a>
-but are still <a lt="idle play state">idle</a> do not have a defined
+but are still [=play state/idle=] do not have a defined
 composite order.
 
 Note, this behavior relies on the fact that disassociating a transition
 from its <a>owning element</a> always causes it to enter (or remain) in the
-<a>idle play state</a>.
+[=play state/idle|idle play state=].
 
 ## Animation cascade level ## {#cascade-level}