[filter-effects-2] Fix spec version in link (#569)

Author: alkorlos

filter-effects-2/Overview.bs

@@ -47,7 +47,7 @@ Inherited: no
 Percentages: n/a
 Computed value: as specified
 Media: visual
-Animation type: see prose in [[filter-effects#animation-of-filters]].
+Animation type: see prose in [[filter-effects-1#animation-of-filters]].
 </pre>
 
 If the value of the 'backdrop-filter' property is ''backdrop-filter/none'' then there is no
@@ -342,7 +342,7 @@ The current definition of mix-blend-mode <a href="https://www.w3.org/TR/composit
 
 <h2 id="priv-sec">Privacy and Security Considerations</h2>
 
-All of the same privacy and security concerns exist for backdrop-filter as do for "standard" filters. See [[filter-effects#tainted-filter-primitives]] for more details.
+All of the same privacy and security concerns exist for backdrop-filter as do for "standard" filters. See [[filter-effects-1#tainted-filter-primitives]] for more details.
 
 <h2 class=no-num id='acknowledgments'>Acknowledgments</h2>