Add isBit

Signed-off-by: Ryszard Rozak <rrozak@antmicro.com>

src/V3AstAttr.h

@@ -574,6 +574,9 @@ public:
                 || m_e == LONGINT || m_e == SHORTINT || m_e == UINT32 || m_e == UINT64
                 || m_e == TIME);
     }
+    bool isBit() const {
+        return m_e == BIT;
+    }
     bool isBitLogic() const {  // Bit/logic vector types; can form a packed array
         return (m_e == LOGIC || m_e == BIT);
     }

src/V3AstNodeDType.h

@@ -459,6 +459,7 @@ public:
         return m.m_keyword;
     }
     bool isBitLogic() const { return keyword().isBitLogic(); }
+    bool isBit() const { return keyword().isBit(); }
     bool isCHandle() const VL_MT_STABLE { return keyword().isCHandle(); }
     bool isDouble() const VL_MT_STABLE { return keyword().isDouble(); }
     bool isEvent() const VL_MT_STABLE { return keyword() == VBasicDTypeKwd::EVENT; }