Merge #13908: [Docs] upgrade rescan time warning from minutes to >1 hour

bb5b1c0b2d [Docs] upgrade rescan time warning from minutes to >1 hour (Mason Simon)

Pull request description:

  When I rescanned just now it took well over an hour. The time warning "may take minutes" didn't prepare me for that.

  ```
  2018-08-08T03:10:17Z [wallet] Still rescanning. At block 174747. Progress=0.008341
  2018-08-08T03:11:17Z [wallet] Still rescanning. At block 204233. Progress=0.024533
  2018-08-08T03:12:17Z [wallet] Still rescanning. At block 221170. Progress=0.038340
  ...
  2018-08-08T04:16:17Z [wallet] Still rescanning. At block 524815. Progress=0.957105
  2018-08-08T04:17:17Z [wallet] Still rescanning. At block 528572. Progress=0.971323
  2018-08-08T04:18:17Z [wallet] Still rescanning. At block 532458. Progress=0.986824
  ```

  This is on a 4-core 4ghz system with a 7200rpm drive.

Tree-SHA512: 722ccf566bfd6a3381fa173e08849cb676fe4c1f1cb2c4b86b07df2a5dc1ca0d54797cbe8fd606cdc2c60fef2be7c98e052460decdac2132ba759cff822132e8

src/wallet/rpcdump.cpp

@@ -115,7 +115,7 @@ UniValue importprivkey(const JSONRPCRequest& request)
             "1. \"privkey\"          (string, required) The private key (see dumpprivkey)\n"
             "2. \"label\"            (string, optional, default=\"\") An optional label\n"
             "3. rescan               (boolean, optional, default=true) Rescan the wallet for transactions\n"
-            "\nNote: This call can take minutes to complete if rescan is true, during that time, other rpc calls\n"
+            "\nNote: This call can take over an hour to complete if rescan is true, during that time, other rpc calls\n"
             "may report that the imported key exists but related transactions are still missing, leading to temporarily incorrect/bogus balances and unspent outputs until rescan completes.\n"
             "\nExamples:\n"
             "\nDump a private key\n"
@@ -268,7 +268,7 @@ UniValue importaddress(const JSONRPCRequest& request)
             "2. \"label\"            (string, optional, default=\"\") An optional label\n"
             "3. rescan               (boolean, optional, default=true) Rescan the wallet for transactions\n"
             "4. p2sh                 (boolean, optional, default=false) Add the P2SH version of the script as well\n"
-            "\nNote: This call can take minutes to complete if rescan is true, during that time, other rpc calls\n"
+            "\nNote: This call can take over an hour to complete if rescan is true, during that time, other rpc calls\n"
             "may report that the imported address exists but related transactions are still missing, leading to temporarily incorrect/bogus balances and unspent outputs until rescan completes.\n"
             "If you have the full public key, you should call importpubkey instead of this.\n"
             "\nNote: If you import a non-standard raw script in hex form, outputs sending to it will be treated\n"
@@ -448,7 +448,7 @@ UniValue importpubkey(const JSONRPCRequest& request)
             "1. \"pubkey\"           (string, required) The hex-encoded public key\n"
             "2. \"label\"            (string, optional, default=\"\") An optional label\n"
             "3. rescan               (boolean, optional, default=true) Rescan the wallet for transactions\n"
-            "\nNote: This call can take minutes to complete if rescan is true, during that time, other rpc calls\n"
+            "\nNote: This call can take over an hour to complete if rescan is true, during that time, other rpc calls\n"
             "may report that the imported pubkey exists but related transactions are still missing, leading to temporarily incorrect/bogus balances and unspent outputs until rescan completes.\n"
             "\nExamples:\n"
             "\nImport a public key with rescan\n"
@@ -1158,7 +1158,7 @@ UniValue importmulti(const JSONRPCRequest& mainRequest)
             "  {\n"
             "     \"rescan\": <false>,         (boolean, optional, default: true) Stating if should rescan the blockchain after all imports\n"
             "  }\n"
-            "\nNote: This call can take minutes to complete if rescan is true, during that time, other rpc calls\n"
+            "\nNote: This call can take over an hour to complete if rescan is true, during that time, other rpc calls\n"
             "may report that the imported keys, addresses or scripts exists but related transactions are still missing.\n"
             "\nExamples:\n" +
             HelpExampleCli("importmulti", "'[{ \"scriptPubKey\": { \"address\": \"<my address>\" }, \"timestamp\":1455191478 }, "