Added linear transponder Doppler calculator (#232)

Co-authored-by: atsunatsu <atsunatsu@users.noreply.github.com>

core/presentation/src/main/res/values-zh/strings.xml

@@ -60,6 +60,9 @@
     <string name="radar_string_no">否</string>
     <string name="radar_string_yes">是</string>
     <string name="radar_visible">日照中</string>
+    <string name="radar_doppler_tx_hint">输入上行频率 (MHz)</string>
+    <string name="radar_doppler_rx_hint">输入下行频率 (MHz)</string>
+    <string name="radar_doppler_offset_hint">偏移 (kHz)</string>
 
     <!-- Map screen -->
     <string name="map_prev">上一个</string>

core/presentation/src/main/res/values/strings.xml

@@ -84,6 +84,9 @@
     <string name="radar_string_no">No</string>
     <string name="radar_string_yes">Yes</string>
     <string name="radar_visible">Visible</string>
+    <string name="radar_doppler_tx_hint">Enter TX freq (MHz)</string>
+    <string name="radar_doppler_rx_hint">Enter RX freq (MHz)</string>
+    <string name="radar_doppler_offset_hint">Offset (kHz)</string>
 
     <!-- Map screen -->
     <string name="map_prev">Prev</string>