[css-text-4] Fix box/element stuff, define propagation.

Author: fantasai

css-text-4/Overview.bs

@@ -274,13 +274,13 @@ Inline breaks between boxes: the 'wrap-before'/'wrap-after' properties</h3>
 		<dt><dfn>auto</dfn>
 		<dd>
 			Lines may break at allowed break points
-			before and after the element,
+			before and after the box,
 			as determined by the line-breaking rules in effect.
 
 		<dt><dfn>avoid</dfn>
 		<dd>
-			Line breaking is suppressed before/after the element:
-			the UA may only break before/after the element
+			Line breaking is suppressed immediately before/after the box:
+			the UA may only break there
 			if there are no other valid break points
 			in the line.
 			If the text breaks,
@@ -299,16 +299,23 @@ Inline breaks between boxes: the 'wrap-before'/'wrap-after' properties</h3>
 
 		<dt><dfn>line</dfn>
 		<dd>
-			Force a line break before/after the element
-			if the element is an inline-level box.
+			Force a line break immediately before/after the box
+			if box is an <a>inline-level</a> box.
 
 		<dt><dfn>flex</dfn>
 		<dd>
-			Force a <a>flex line</a> break before/after the element
-			if the element is a flex item
-			in a multi-line flex container.
+			Force a <a>flex line</a> break immediately before/after the box
+			if the box is a <a>flex item</a>
+			in a <a href="http://www.w3.org/TR/css-flexbox-1/#multi_line">multi-line flex container</a>.
 	</dl>
 
+	Forced line breaks on <a>inline-level</a> boxes propagate upward
+	through any parent <a>inline boxes</a>
+	the same way forced breaks on <a>block-level</a> boxes propagate upward
+	through any parent <a>block boxes</a>
+	in the same <a>fragmentation context</a>.
+	[[!CSS3-BREAK]]
+
 <h3 id="wrap-inside">
 Line breaks within boxes: the 'wrap-inside' property</h3>
 
@@ -327,22 +334,22 @@ Line breaks within boxes: the 'wrap-inside' property</h3>
 		<dt><dfn>auto</dfn>
 		<dd>
 			Lines may break at allowed break points
-			within the element,
+			within the box,
 			as determined by the line-breaking rules in effect.
 
 		<dt><dfn>avoid</dfn>
 		<dd>
-			Line breaking is suppressed within the element:
-			the UA may only break within the element
+			Line breaking is suppressed within the box:
+			the UA may only break within the box
 			if there are no other valid break points in the line.
 			If the text breaks,
 			line-breaking restrictions are honored as for
 			''wrap-inside/auto''.
 
-			If elements with ''wrap-inside/avoid'' are nested
-			and the UA must break within these elements,
-			a break in an outer element must be used
-			before a break within an inner element may be used.
+			If boxes with ''wrap-inside/avoid'' are nested
+			and the UA must break within these boxes,
+			a break in an outer box must be used
+			before a break within an inner box may be used.
 	</dl>
 
 <h4 id="example-avoid">