[css-logical-1] Fix links: CSS21 -> CSS2

Author: fantasai

css-logical-1/Overview.bs

@@ -10,7 +10,7 @@ TR: https://www.w3.org/TR/css-logical-1/
 Previous version: https://www.w3.org/TR/2017/WD-css-logical-1-20170518/
 Editor: Rossen Atanassov, Microsoft, ratan@microsoft.com, w3cid 49885
 Editor: Elika J. Etemad / fantasai, Invited Expert, http://fantasai.inkedblade.net/contact, w3cid 35400
-Abstract: This module introduces logical properties and values that provide the author with the ability to control layout through logical, rather than physical, direction and dimension mappings. The module defines logical properties and values for the features defined in [[CSS21]]. These properties are writing-mode relative equivalents of their corresponding physical properties.
+Abstract: This module introduces logical properties and values that provide the author with the ability to control layout through logical, rather than physical, direction and dimension mappings. The module defines logical properties and values for the features defined in [[CSS2]]. These properties are writing-mode relative equivalents of their corresponding physical properties.
 Ignored Terms: div, dl, dfn
 Ignored Vars: *
 Link Defaults: css2 (property) width/height/min-width/min-height/max-width/max-height
@@ -242,15 +242,15 @@ Flow-Relative Values for the 'resize' Property</h3>
 <h2 id="page">
 Flow-Relative Page Classifications</h2>
 
-  In CSS, all pages are classified by user agents as either left pages or right pages. [[!CSS21]]
+  In CSS, all pages are classified by user agents as either left pages or right pages. [[!CSS2]]
   Which page is first in a spread, however,
   depends on whether the page progression is left-to-right or right-to-left.
 
   To allow control of page breaking to the page
   that is on the earlier or later side of a spread,
   rather than to the left or right side of a spread,
   this module introduces the following additional keywords
-  for the 'page-break-after' and 'page-break-before' properties [[!CSS21]]:
+  for the 'page-break-after' and 'page-break-before' properties [[!CSS2]]:
 
   <dl dfn-type="value" dfn-for="logical-page">
     <dt><dfn>recto</dfn>
@@ -270,7 +270,7 @@ Flow-Relative Page Classifications</h2>
   Although authors typically place page numbers using physical placements,
   the contents of headers often follows conventions depending
   on which page in the spread is earlier.
-  Therefore the following flow-relative <a href="https://www.w3.org/TR/CSS21/page.html#page-selectors">page selectors</a>
+  Therefore the following flow-relative <a href="https://www.w3.org/TR/CSS2/page.html#page-selectors">page selectors</a>
   are also added to support flow-relative page selection:
 
   <dl dfn-type="value" dfn-for="logical-page-selector">
@@ -698,7 +698,7 @@ Four-Directional Shorthand Properties: the 'margin', 'padding', 'border-width',
     and to specify the expected impact on the interpretation
     of whatever syntactic switch is ultimately chosen.
 
-  The following [[!CSS21]] shorthand properties
+  The following [[!CSS2]] shorthand properties
   accept the ''margin/logical'' keyword:
   <ul>
     <li>'inset'