[mediaqueries-4] Fix grammar so you can't just totally omit the comparator in range syntax. Fixes #2790.

Author: tabatkins

mediaqueries-4/Overview.bs

@@ -743,11 +743,11 @@ Using “min-” and “max-” Prefixes On Range Features</h4>
 		it does not take into account the possibility of fractional viewport sizes which can occur as a result of non-integer pixel densities
 		(e.g. on high-dpi displays or as a result of zooming/scaling).
 		Any viewport widths that fall between 320px and 321px will result in none of the styles being applied.
-		
+
 		One approach to work around this problem is to increase the precision of the values used for the comparison. Using the example above,
 		changing the second comparison value to 320.01px significantly reduces the change that a viewport width on a device would fall
 		between the cracks.
-		
+
 		<pre>
 			@media (max-width: 320px) { /* styles for viewports <= 320px */ }
 			@media (min-width: 320.01px) { /* styles for viewports >= 320.01px */ }
@@ -869,12 +869,16 @@ Syntax</h2>
 	<dfn>&lt;media-feature></dfn> = ( [ <<mf-plain>> | <<mf-boolean>> | <<mf-range>> ] )
 	<dfn>&lt;mf-plain></dfn> = <<mf-name>> : <<mf-value>>
 	<dfn>&lt;mf-boolean></dfn> = <<mf-name>>
-	<dfn>&lt;mf-range></dfn> = <<mf-name>> [ '<' | '>' ]? '='? <<mf-value>>
-	           | <<mf-value>> [ '<' | '>' ]? '='? <<mf-name>>
-	           | <<mf-value>> '<' '='? <<mf-name>> '<' '='? <<mf-value>>
-	           | <<mf-value>> '>' '='? <<mf-name>> '>' '='? <<mf-value>>
+	<dfn>&lt;mf-range></dfn> = <<mf-name>> <<mf-comparison>> <<mf-value>>
+	           | <<mf-value>> <<mf-comparison>> <<mf-name>>
+	           | <<mf-value>> <<mf-lt>> <<mf-name>> <<mf-lt>> <<mf-value>>
+	           | <<mf-value>> <<mf-gt>> <<mf-name>> <<mf-gt>> <<mf-value>>
 	<dfn>&lt;mf-name></dfn> = <<ident>>
 	<dfn>&lt;mf-value></dfn> = <<number>> | <<dimension>> | <<ident>> | <<ratio>>
+	<dfn>&lt;mf-lt></dfn> = '<' '='?
+	<dfn>&lt;mf-gt></dfn> = '>' '='?
+	<dfn>&lt;mf-eq></dfn> = '='
+	<dfn>&lt;mf-comparison></dfn> = <<mf-lt>> | <<mf-gt>> | <<mf-eq>>
 
 	<dfn>&lt;general-enclosed></dfn> = [ <<function-token>> <<any-value>> ) ] | ( <<ident>> <<any-value>> )
 	</pre>
@@ -1735,19 +1739,19 @@ Note: the '@media/hover', '@media/any-hover', '@media/pointer', and '@media/any-
 		</style>
 	</div>
 
-	The 'pointer' and 'hover' features relate to the characteristics of the “primary” pointing device, 
+	The 'pointer' and 'hover' features relate to the characteristics of the “primary” pointing device,
 	while 'any-pointer' and 'any-hover' can be used to query the properties of all potentially available pointing devices.
 
-	Note: While this specification does not define how user agents should decide what the “primary” pointing device is, 
-	the expectation is that user agents should make this determination 
-	by combining knowledge about the device/environment they are running on, 
-	the number and type of pointing devices available, 
+	Note: While this specification does not define how user agents should decide what the “primary” pointing device is,
+	the expectation is that user agents should make this determination
+	by combining knowledge about the device/environment they are running on,
+	the number and type of pointing devices available,
 	and a notion of which of these is generally and/or currently being used.
 	In situations where the primary input mechanism for a device is not a pointing device,
 	but there is a secondary – and less frequently used – input that is a pointing devices,
 	the user agent may decide to treat the non-pointing device as the primary (resulting in 'pointer: none').
-	user agents may also decide to dynamically change what type of pointing device is deemed to be primary, 
-	in response to changes in the user environment 
+	user agents may also decide to dynamically change what type of pointing device is deemed to be primary,
+	in response to changes in the user environment
 	or in the way the user is interacting with the UA.
 
 	Note: The 'pointer', 'hover', 'any-pointer' and 'any-hover' features only relate to the characteristics,
@@ -2283,7 +2287,7 @@ but for the sake of privacy and security,
 UAs have been allowed to report inacurate information.
 
 The <a href="http://www.w3.org/2001/tag/">TAG</a> has developed a <a href="https://www.w3.org/TR/security-privacy-questionnaire/">self-review questionaire</a>
-to help editors and Working Groups evaluate the risks introduced by their specifications. 
+to help editors and Working Groups evaluate the risks introduced by their specifications.
 Answers are provided below.