fix: first '_' character not shown in menu item (sourcegit-scm#313)

Author: love-linger

src/Resources/Styles.axaml

@@ -781,7 +781,7 @@
                                     ContentTemplate="{TemplateBinding HeaderTemplate}"
                                     VerticalAlignment="Center"
                                     HorizontalAlignment="Stretch"
-                                    RecognizesAccessKey="True"/>
+                                    RecognizesAccessKey="False"/>
                   <TextBlock x:Name="PART_InputGestureText"
                              Grid.Column="2"
                              Classes="CaptionTextBlockStyle"

src/Views/Repository.axaml

@@ -488,7 +488,7 @@
             </TextBox.InnerRightContent>
           </TextBox>
 
-          <Popup PlacementTarget="#TxtSearchCommitsBox"
+          <Popup PlacementTarget="{Binding #TxtSearchCommitsBox}"
                  Placement="BottomEdgeAlignedLeft"
                  HorizontalOffset="-8" VerticalAlignment="-8"
                  IsOpen="{Binding IsSearchCommitSuggestionOpen}">