Update fetch.bs

Co-authored-by: Anne van Kesteren <[email protected]>

Author: noamr

fetch.bs

@@ -3079,7 +3079,7 @@ these steps:
 </div>
 
 <div algorithm="check-preemptive-operation-csp">
-<p>To <dfn>Check CSP for preemptive operation</dfn>, given an
+<p>To <dfn>check CSP for preemptive operation</dfn>, given an
 <a>environment settings object</a> <var>environment</var>, and a <a for=/>URL</a> <var>url</var>,
 run these steps: