update GEM, adding GEM into solid.xml

compact/GEM_sidis.xml

 <lccdd>
   <detectors>
-    <detector id="2" name="GEMTracker_SIDIS" vis="RedVis" type="GaplessGEMTrackerDisc" readout="GEMTrackerHits" >
+    <detector id="2" name="GEMTracker_SIDIS" vis="RedVis" type="SoLID_GEMTrackerDisc" readout="GEMTrackerHits" >
       <module name="Module_A" id="1" inner_r="50.0*cm"  outer_r="118.0*cm" segments="30">
         <slice name="drift_cathode" material="Kapton" thickness="0.100*mm"/>
         <slice name="drift_gas1" material="GEMGas" thickness="3.0*mm"/>

solid.xml

@@ -64,6 +64,7 @@
     <!--<include ref="compact/LAEC.xml"/>
     <include ref="compact/FAEC.xml"/>-->
     <include ref="compact/LGC.xml"/>
+    <include ref="compact/GEM_sidis.xml"/>
   </detectors>
 
   <!--  Definition of the readout segmentation/definition  -->

src/GEMTrackerDiscSOLID_geo.cpp → src/GEMTrackerDisc_geo.cpp

+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright (C) 2024 Chao Peng, Whitney Armstrong
+
 #include "DD4hep/DetFactoryHelper.h"
 #include "DD4hep/Printout.h"
 #include "TMath.h"
@@ -79,4 +82,4 @@ static Ref_t create_detector(Detector& lcdd, xml_h e, SensitiveDetector sens)
   return sdet;
 }
 
-DECLARE_DETELEMENT(GEMTrackerDiscSOLID,create_detector)
+DECLARE_DETELEMENT(SoLID_GEMTrackerDisc, create_detector)