fixing relative path for example link so as to make it work with web.external-url configurations

Signed-off-by: Devendra <d3v3ndrasr@gmail.com>

Author: Devendra

.gitignore

@@ -1,2 +1,3 @@
 /promlens
+.idea
 /npm_licenses.tar.bz2

app/src/PromLens/PromLensUI.tsx

@@ -89,7 +89,7 @@ const PromLens: FC<PromLensUIStateProps & PromLensUIOwnProps & PathPrefixProps>
           <strong className="mr-auto">First time here?</strong>
         </Toast.Header>
         <Toast.Body>
-          Check out an <a href="/?example">example page</a> with multiple queries or take a{' '}
+          Check out an <a href="./?example">example page</a> with multiple queries or take a{' '}
           <a href="https://promlens.com/">feature tour</a>.
         </Toast.Body>
       </Toast>