[css-display-3] Adjust wording around block-level boxes. Fixes #1704.

Author: fantasai

css-display-3/Overview.bs

@@ -316,12 +316,14 @@ Outer Display Roles for Flow Layout: the ''block'', ''inline'', and ''run-in'' k
 	<dl dfn-type="value" dfn-for="display, <display-outside>">
 		<dt><dfn>block</dfn>
 		<dd>
-			The element generates a <dfn dfn for>block-level box</dfn>
+			The element generates a box that is
+			<dfn dfn for lt="block-level box">block-level</dfn>
 			when placed in <a>flow layout</a>. [[!CSS2]]
 
 		<dt><dfn>inline</dfn>
 		<dd>
-			The element generates an <dfn dfn for>inline-level box</dfn>
+			The element generates a box that is
+			<dfn dfn for lt="inline-level box">inline-level</dfn>
 			when placed in <a>flow layout</a>. [[!CSS2]]
 
 		<dt><dfn>run-in</dfn>

css-flexbox-1/Overview.bs

@@ -506,11 +506,13 @@ Flex Containers: the ''flex'' and ''inline-flex'' 'display' values</h2>
 	<dl dfn-type=value dfn-for=display>
 		<dt><dfn>flex</dfn>
 		<dd>
-			This value causes an element to generate a block-level <a>flex container</a> box.
+			This value causes an element to generate a <a>flex container</a> box
+			that is <a>block-level</a> when placed in <a>flow layout</a>.
 
 		<dt><dfn>inline-flex</dfn>
 		<dd>
-			This value causes an element to generate an inline-level <a>flex container</a> box.
+			This value causes an element to generate a <a>flex container</a> box
+			that is <a>inline-level</a> when placed in <a>flow layout</a>.
 	</dl>
 
 	A <a>flex container</a> establishes a new <dfn export>flex formatting context</dfn> for its contents.

css-grid-1/Overview.bs

@@ -838,11 +838,13 @@ Establishing Grid Containers: the ''display/grid'' and ''inline-grid'' 'display'
 	<dl dfn-for="display" dfn-type=value>
 		<dt><dfn>grid</dfn>
 		<dd>
-			This value causes an element to generate a block-level <a>grid container</a> box.
+			This value causes an element to generate a <a>grid container</a> box
+			that is <a>block-level</a> when placed in <a>flow layout</a>.
 
 		<dt><dfn>inline-grid</dfn>
 		<dd>
-			This value causes an element to generate an inline-level <a>grid container</a> box.
+			This value causes an element to generate an <a>grid container</a> box
+			that is <a>inline-level</a> when placed in <a>flow layout</a>.
 	</dl>
 
 	A <dfn export>grid container</dfn> establishes a new <dfn export>grid formatting context</dfn> for its contents.

css-tables-3/Overview.bs

@@ -145,12 +145,12 @@ spec:css-sizing-3; type:property; text:box-sizing
 
 	<dl id="display-types">
 		<dt><dfn>table</dfn> (equivalent to HTML: &lt;table&gt;)
-		<dd>Specifies that an element defines a block-level table:
-			it is a rectangular block that participates in a block formatting context.
+		<dd>Specifies that an element defines a table
+			that is <a>block-level</a> when placed in <a>flow layout</a>.
 
 		<dt><dfn>inline-table</dfn> (equivalent to HTML: &lt;table&gt;)
-		<dd>Specifies that an element defines an inline-level table:
-			it is a rectangular block that participates in an inline formatting context).
+		<dd>Specifies that an element defines a table
+			that is <a>inline-level</a> when placed in <a>flow layout</a>.
 
 		<dt><dfn>table-row</dfn> (equivalent to HTML: &lt;tr&gt;)
 		<dd>Specifies that an element is a row of cells.