feat(stores): add ledger specific xpub help

problem: maximum of 20 ledger accounts are being listed in the derivation-scheme select
solution: help users with i.e. multiple ledger accounts by providing link to docs for detailed info on where to find the xpub key manually

BTCPayServer/Views/Stores/AddDerivationSchemes_HardwareWalletDialogs.cshtml

@@ -19,8 +19,22 @@
                 <p id="no-ledger-info" style="display: none;">
                     No ledger wallet detected. If you own one, use chrome, open the app, and refresh this page.
                 </p>
-                <div id="ledger-info" class="display-when-ledger-connected">
-                    <span>A ledger wallet is detected, which account do you want to use? No need to paste manually xpub if your ledger device was detected. Just select derivation scheme from the list bellow and xpub will automatically populate.</span>
+                <div id="no-ledger-info" class="display-when-ledger-connected">
+                    <p>
+                        A ledger wallet is detected, which account do you want to use? No need to paste manually
+                        xpub if your ledger device was detected. Just select derivation scheme from the list
+                        bellow and xpub will automatically populate.
+                    </p>
+
+                    <p>
+                        <a href="https://docs.btcpayserver.org/getting-started/connectwallet/ledgerwallet#manual-setup"
+                            title="Open Ledger wallet manual setup docs"
+                            target="_blank"
+                            rel="noopener noreferrer"
+                        >
+                            Can't find your account in the select?
+                        </a>
+                    </p>
                 </div>
             </div>
             <div class="modal-footer">
@@ -63,7 +77,6 @@
                 <button type="button" class="btn btn-secondary" data-dismiss="modal">Close</button>
                 <button type="submit" class="btn btn-primary">Submit</button>
             </div>
-
         </form>
     </div>
 </div>