[cssom-1] Fix links to <alpha-value> and (pre-defined) keywords (w3c#9420)

Author: cdoublev

cssom-1/Overview.bs

@@ -134,6 +134,7 @@ spec:css-fonts-4; type:descriptor; text:font-feature-settings
 spec:css-fonts-4; type:descriptor; text:font-stretch
 spec:css-fonts-4; type:descriptor; text:font-weight
 spec:css-fonts-4; type:descriptor; text:font-style
+spec:css-values-4; type:dfn; text:keyword
 </pre>
 
 <style>
@@ -2794,7 +2795,7 @@ To
 depends on the component, as follows:
 
 <dl class="switch">
- <dt>keyword
+ <dt>[=keyword=]
  <dd>The keyword
  <a lt="ASCII lowercase">converted to ASCII lowercase</a>.
 
@@ -2820,7 +2821,7 @@ depends on the component, as follows:
 
  Issue: Should author specified values be normalized for case, the same as computed values? Or should original case be preserved?
 
- <dt><<alphavalue>>
+ <dt><<alpha-value>>
  <dd>
   If the value is internally represented as an integer between 0 and 255 inclusive (i.e. 8-bit unsigned integer),
   follow these steps: