Update personal_getBalance to return a string.

Oversight on my end. Also adds missing documentation. Another such 
oversight.

docs/RPC/Personal.md

@@ -83,6 +83,12 @@ The result is an array of objects, each as follows:
 - `hash`    (string)
 - `nonce`   (int)
 
+### `getBalance`
+
+`getBalance` replies with the sum of the value of every UTXO known to the node's Wallet, AKA its balance. If you only want the balance for a specific address, use `transactions_getBalance`.
+
+The result is a string of the balance.
+
 ### `getTransactionTemplate`
 
 `getTransactionTemplate` replies with a signable transaction template usable by a program with the relevant private keys.

e2e/Tests/RPC/Personal/WatchWalletTest.py

@@ -172,12 +172,14 @@ def test() -> None:
       raise TestError("WatchWallet Meros couldn't get its UTXOs.")
 
     #Also test balance getting.
-    if rpc.call("personal", "getBalance") != sum(
-      [
-        int(
-          rpc.call("transactions", "getTransaction", {"hash": send.hex()})["outputs"][0]["amount"]
-        ) for send in sends[:2]
-      ]
+    if rpc.call("personal", "getBalance") != str(
+      sum(
+        [
+          int(
+            rpc.call("transactions", "getTransaction", {"hash": send.hex()})["outputs"][0]["amount"]
+          ) for send in sends[:2]
+        ]
+      )
     ):
       raise TestError("WatchWallet Meros couldn't get its balance.")
 
@@ -201,12 +203,14 @@ def test() -> None:
       raise TestError("WatchWallet Meros couldn't get its UTXOs.")
 
     #Again test the balance.
-    if rpc.call("personal", "getBalance") != sum(
-      [
-        int(
-          rpc.call("transactions", "getTransaction", {"hash": send.hex()})["outputs"][0]["amount"]
-        ) for send in sends[:3]
-      ]
+    if rpc.call("personal", "getBalance") != str(
+      sum(
+        [
+          int(
+            rpc.call("transactions", "getTransaction", {"hash": send.hex()})["outputs"][0]["amount"]
+          ) for send in sends[:3]
+        ]
+      )
     ):
       raise TestError("WatchWallet Meros couldn't get its balance.")
 

src/Interfaces/RPC/Modules/PersonalModule.nim

@@ -112,12 +112,14 @@ proc module*(
             "nonce": utxo.utxo.nonce
           })
 
-      proc getBalance(): uint64 {.requireAuth, forceCheck: [].} =
+      proc getBalance(): string {.requireAuth, forceCheck: [].} =
+        var balance: uint64 = 0
         for utxo in functions.personal.getUTXOs():
           try:
-            result += functions.transactions.getTransaction(utxo.utxo.hash).outputs[utxo.utxo.nonce].amount
+            balance += functions.transactions.getTransaction(utxo.utxo.hash).outputs[utxo.utxo.nonce].amount
           except IndexError as e:
             panic("Had a UTXO for a non-existent Transaction: " & e.msg)
+        result = $balance
 
       proc getTransactionTemplate(
         #_JSON is used to distinguish the name from the below variables, not out of necessity due to using a keyword.