[css-easing-1][css-easing-2] Harmonize definitions of the linear keyword while avoiding normative ref from level 1 to 2, fix #10734

Author: svgeesus

css-easing-1/Overview.bs

@@ -42,6 +42,9 @@ WPT Display: closed
   }
 }
 </pre>
+<pre class="link-defaults">
+  spec:css-easing-1; type:dfn; text:easing function
+</pre>
 
 Introduction {#introduction}
 ============================
@@ -134,14 +137,11 @@ The syntax for specifying an [=easing function=] is as follows:
 
 <h3 id=the-linear-easing-function oldids=linear-timing-function-section>The linear easing function: ''linear''</h3>
 
-The <dfn export lt="linear easing function|linear timing function">linear easing
-function</dfn> is an identity function
-meaning that its [=output progress value=] is equal to the
+The <dfn dfn-type=value for="easing-function">linear</dfn> keyword
+produces an identity linear [=easing function=]
+whose [=output progress value=] is equal to the
 [=input progress value=] for all inputs.
 
-The syntax for the [=linear easing function=] is simply the
-<dfn dfn-type=value for=easing-function>linear</dfn> keyword.
-
 
 <h3 id=cubic-bezier-easing-functions oldids=cubic-bezier-timing-functions>Cubic
 B&eacute;zier easing functions:

css-easing-2/Overview.bs

@@ -449,23 +449,12 @@ It returns an [=output progress value=].
 <h3 id=the-linear-easing-keyword oldids=linear-timing-function-section>The linear easing keyword: ''linear''</h3>
 
 The <dfn dfn-type=value for="<easing-function>">linear</dfn> keyword
-produces a [=linear easing function=]
-with two [=linear easing function/points=]:
-
-1.   : [=linear easing point/input=]
-     :: 0
-     : [=linear easing point/output=]
-     :: 0
-
-1.   : [=linear easing point/input=]
-     :: 1
-     : [=linear easing point/output=]
-     :: 1
-
-Note: This results in an identity function,
-meaning that its [=output progress value=] is equal to the
+produces an identity [=linear easing function=]
+whose [=output progress value=] is equal to the
 [=input progress value=] for all inputs.
 
+This gives the same result as ''linear(0, 1)''.
+
 Note: Although this produces a [=linear easing function=],
 uses of the keyword ''linear'' always serialize as-is, to ''linear''.
 Whereas the function equivalent ''linear(0, 1)'' will serialize to ''linear(0 0%, 1 100%)''.