Several fixes to make glslang compile with higher warning levels.

SPIRV/SpvPostProcess.cpp

@@ -181,6 +181,7 @@ void Builder::postProcessType(const Instruction& inst, Id typeId)
             else if (width == 8)
                 addCapability(CapabilityInt8);
         }
+        [[fallthrough]]; // @MEWIN - 2022-12-07 - Added this to get rid of implicit-fallthrough warning.
     default:
         if (basicTypeOp == OpTypeInt) {
             if (width == 16)

SPIRV/doc.h

@@ -240,8 +240,8 @@ public:
     OperandParameters operands;
 
 protected:
-    int typePresent   : 1;
-    int resultPresent : 1;
+    unsigned typePresent   : 1; // @MEWIN - 2022-12-07 - Changed to unsigned to get rid of -Woverflow warnings.
+    unsigned resultPresent : 1; // @MEWIN - 2022-12-07 - Changed to unsigned to get rid of -Woverflow warnings.
 };
 
 // The set of objects that hold all the instruction/operand