Editorial: clean up enumerated attribute preambles

Helps with #9832.

source

@@ -46307,9 +46307,7 @@ interface <dfn interface>HTMLInputElement</dfn> : <span>HTMLElement</span> {
 
   <p>The <dfn element-attr for="input"><code data-x="attr-input-type">type</code></dfn> attribute
   controls the data type (and associated control) of the element. It is an <span>enumerated
-  attribute</span>. The following table lists the keywords and states for the attribute &mdash; the
-  keywords in the left column map to the states in the cell in the second column on the same row as
-  the keyword.</p>
+  attribute</span> with the following keywords and states:</p>
 
   <table id="attr-input-type-keywords">
    <thead>
@@ -52742,9 +52740,7 @@ interface <dfn interface>HTMLButtonElement</dfn> : <span>HTMLElement</span> {
 
   <p>The <dfn element-attr for="button"><code data-x="attr-button-type">type</code></dfn> attribute
   controls the behavior of the button when it is activated. It is an <span>enumerated
-  attribute</span>. The following table lists the keywords and states for the attribute &mdash; the
-  keywords in the left column map to the states in the cell in the second column on the same row as
-  the keyword.</p>
+  attribute</span> with the following keywords and states:</p>
 
   <table>
    <thead>