[css-pseudo-4] Gloss in-flow/out-of-flow jargon

Author: cvrebert

css-pseudo-4/Overview.bs

@@ -491,12 +491,12 @@ Finding the First-Letter Text</h4>
   Its [=first-letter text=] is the first such [=inline-level content=]
   participating in the [=inline formatting context=]
   of its [=originating element=]’s [=first formatted line=],
-  if it is not preceded by any other in-flow content
+  if it is not preceded by any other [=in-flow=] content
   (such as images or inline tables) on its line.
 
   For this purpose, any [=marker boxes=] are ignored,
-  as if they were out-of-flow.
-  However, if an element has in-flow ''::before'' or ''::after'' content,
+  as if they were [=out-of-flow=].
+  However, if an element has [=in-flow=] ''::before'' or ''::after'' content,
   the [=first-letter text=] is selected from the content of the element
   <em>including</em> that generated content.