Update search.en.html

Fixed two typos

invenio_app_rdm/theme/templates/semantic-ui/invenio_app_rdm/help/search.en.html

@@ -235,7 +235,7 @@ <h4>Proximity searches</h4>
     in exactly the same order, and thus for instance would not match a record
     containing the phrase <em>"open access and science"</em>. A proximity search
     allows that the terms are not in the exact order and may include other terms
-    inbetween. The degree of flexiblity is specified by an integer afterwards:
+    in between. The degree of flexibility is specified by an integer afterwards:
   </p>
   <p>
     <strong>Example:</strong>