Add notes on voting for private chain (#1376)

Author: NeoDashboard

docs/en-us/develop/network/private-chain/private-chain2.md

@@ -340,4 +340,7 @@ Here we want to send NEO from the contract address to the normal address.
 
    ![image](../assets/balance.png)
 
-Similarly, you can refer to the preceding steps to withdraw GAS from the multi-party signature address.
+Similarly, you can refer to the preceding steps to withdraw GAS from the multi-party signature address.
+
+## Note on voting
+New committee election will start only after you register 4 candidates and at least 20M NEO are used for voting [see here](https://github.com/neo-project/neo/blob/65822cf81cbea943e3cdaf362ee022d1624fd22d/src/Neo/SmartContract/Native/NeoToken.cs#L517).

docs/en-us/develop/network/private-chain/solo.md

@@ -166,3 +166,5 @@ In the genesis block of the Neo network, 100 million NEO and 30 million GAS are
 
    For more Neo-CLI commands refer to [CLI command reference](../../../node/cli/cli.md).
 
+## Note on voting
+New committee election will start only after you register one candidate and at least 20M NEO are used for voting [see here](https://github.com/neo-project/neo/blob/65822cf81cbea943e3cdaf362ee022d1624fd22d/src/Neo/SmartContract/Native/NeoToken.cs#L517).

docs/zh-cn/develop/network/private-chain/private-chain2.md

@@ -341,4 +341,8 @@ start cmd /k "cd c4 &&ping localhost -n 3 > nul&& dotnet neo-cli.dll"
 
    ![image](../assets/balance.png)
 
-参考前面提取 NEO 进行的多方签名操作，同样可以提取 GAS 到目标地址。
+参考前面提取 NEO 进行的多方签名操作，同样可以提取 GAS 到目标地址。
+
+
+## 投票注意事项
+只有在您注册 4 名候选人并且至少使用 20M NEO 用于投票后，新的委员会选举才会开始[参见此处](https://github.com/neo-project/neo/blob/65822cf81cbea943e3cdaf362ee022d1624fd22d/src/Neo/SmartContract/Native /NeoToken.cs#L517)

docs/zh-cn/develop/network/private-chain/solo.md

@@ -159,3 +159,6 @@ Neo-CLI 支持单节点模式下正常生成区块，只需一个节点即可正
    > 每次转账都会消耗少量 GAS 作为手续费，请确保转账时有足够的 GAS （一般不超过 0.02 个gas）。
 
    节点操作详细指令可参照[CLI 命令参考](../../../node/cli/cli.md)。
+
+## 投票注意事项
+只有在您注册一名候选人并且至少使用 20M NEO 用于投票后，新的委员会选举才会开始[参见此处](https://github.com/neo-project/neo/blob/65822cf81cbea943e3cdaf362ee022d1624fd22d/src/Neo/SmartContract/Native /NeoToken.cs#L517)