[selectors-4] Add some parentheses.

Author: fantasai

selectors-4/Overview.bs

@@ -555,8 +555,8 @@ Structure and Terminology</h3>
 	<a>ID selector</a>,
 	or <a>pseudo-class</a>
 	is a <a>simple selector</a>.
-	It is represented by <<simple-selector>>
-	in the selectors <a href="#grammar">grammar</a>.
+	(It is represented by <<simple-selector>>
+	in the selectors <a href="#grammar">grammar</a>.)
 	A given element is said to <a>match</a> a <a>simple selector</a>
 	when that <a>simple selector</a>,
 	as defined in this specification and in accordance with the <a>document language</a>,
@@ -569,8 +569,8 @@ Structure and Terminology</h3>
 	If it contains a <a>type selector</a> or <a>universal selector</a>,
 	that selector must come first in the sequence.
 	Only one type selector or universal selector is allowed in the sequence.
-	A <a>compound selector</a> is represented by <<compound-selector>>
-	in the selectors <a href="#grammar">grammar</a>.
+	(A <a>compound selector</a> is represented by <<compound-selector>>
+	in the selectors <a href="#grammar">grammar</a>.)
 	A given element is said to <a>match</a> a <a>compound selector</a>
 	when it matches all <a>simple selectors</a> in the <a>compound selector</a>.
 
@@ -595,8 +595,8 @@ Structure and Terminology</h3>
 	It represents a set of simultaneous conditions
 	on a set of elements in the particular relationships
 	described by its <a>combinators</a>.
-	Complex selectors are represented by <<complex-selector>>
-	in the selectors <a href="#grammar">grammar</a>.
+	(Complex selectors are represented by <<complex-selector>>
+	in the selectors <a href="#grammar">grammar</a>.)
 	A given element is said to <a>match</a> a <a>complex selector</a>
 	when there exists a list of elements,
 	each matching a corresponding <a>compound selector</a> in the <a>complex selector</a>,
@@ -620,9 +620,9 @@ Structure and Terminology</h3>
 	when the type is either unimportant or specified in the surrounding prose;
 	if the type is important and unspecified,
 	it defaults to meaning a <a>list of complex selectors</a>.
-	See [[#grouping]] for additional information on <a>selector lists</a>
+	(See [[#grouping]] for additional information on <a>selector lists</a>
 	and the various <<*-selector-list>> productions in the <a href="#grammar">grammar</a>
-	for their formal syntax.
+	for their formal syntax.)
 	A given element is said to <a>match</a> a <a>selector list</a>
 	when it matches any (at least one) of the <a>selectors</a>
 	in that <a>selector list</a>.
@@ -1840,7 +1840,7 @@ The Directionality Pseudo-class: '':dir()''</h3>
 	based on a combination of the <code>dir</code> attribute, the surrounding text, and other factors.
 	As another example, the <code>its:dir</code> and <code>dirRule</code> element
 	of the Internationalization Tag Set [[ITS20]]
-	are able to define the directionality of an element in [[XML]].
+	are able to define the directionality of an element in [[XML10]].
 
 	The '':dir()'' pseudo-class does not select based on stylistic
 	states&#8212;for example, the CSS 'direction' property does not affect