[css-text-decor] Minor wording tweak

Author: fantasai

css-text-decor/Overview.html

@@ -1188,7 +1188,7 @@ <h3 id="line-position">
   <p>Some font formats (such as OpenType) can offer information about the
    appropriate position of a line decoration. The UA should use such
    information (such as the underline thickness, or appropriate alphabetic
-   alignment) from the font wherever appropriate.
+   underline position) from the font wherever appropriate.
 
   <p class=note>Typically, OpenType font metrics give the position of an
    ‘<code class=css>alphabetic</code>’ underline; in some cases
@@ -1755,7 +1755,9 @@ <h2 id=text-shadow-property><span class=secno>4. </span> Text Shadows: the
    adjacent elements belonging to the same stack level and stacking context.
    (This may mean that the exact stack level of the shadows depends on
    whether the element has a border or background: the exact stacking
-   behavior of text shadows is thus UA-defined.)
+   behavior of text shadows is thus UA-defined.) It is undefined whether a
+   given shadow layer shadows each glyph or decoration independently or if
+   the text and/or decorations are flattened and then shadowed.
 
   <p>Unlike ‘<code class=property>box-shadow</code>’, text shadows are
    not clipped to the shadowed shape and may show through if the text is

css-text-decor/Overview.src.html

@@ -823,8 +823,10 @@ <h3 id="line-position">
 -->
   <p>Some font formats (such as OpenType) can offer information
     about the appropriate position of a line decoration.
-    The UA should use such information (such as the underline thickness,
-    or appropriate alphabetic alignment) from the font wherever appropriate.
+    The UA should use such information
+    (such as the underline thickness,
+    or appropriate alphabetic underline position)
+    from the font wherever appropriate.
 
   <p class="note">Typically, OpenType font metrics give the position of an ''alphabetic'' underline;
     in some cases (especially in CJK fonts), it gives the position of a ''under left'' underline.