Merge bitcoin/bitcoin#32520: Remove legacy Parse(U)Int*

faf55fc80b doc: Remove ParseInt mentions in documentation (MarcoFalke)
3333282933 refactor: Remove unused Parse(U)Int* (MarcoFalke)
fa84e6c36c bitcoin-tx: Reject + sign in MutateTxDel* (MarcoFalke)
face2519fa bitcoin-tx: Reject + sign in vout parsing (MarcoFalke)
fa8acaf0b9 bitcoin-tx: Reject + sign in replaceable parsing (MarcoFalke)
faff25a558 bitcoin-tx: Reject + sign in locktime (MarcoFalke)
dddd9e5fe3 bitcoin-tx: Reject + sign in nversion parsing (MarcoFalke)
fab06ac037 rest: Use SAFE_CHARS_URI in SanitizeString error msg (MarcoFalke)
8888bb499d rest: Reject + sign in /blockhashbyheight/ (MarcoFalke)
fafd43c691 test: Reject + sign when parsing regtest deployment params (MarcoFalke)
fa123afa0e Reject + sign when checking -ipcfd (MarcoFalke)
fa479857ed Reject + sign in SplitHostPort (MarcoFalke)
fab4c2967d net: Reject + sign when parsing subnet mask (MarcoFalke)
fa89652e68 init: Reject + sign in -*port parsing (MarcoFalke)
fa9c45577d cli: Reject + sign in -netinfo level parsing (MarcoFalke)
fa98041325 refactor: Use ToIntegral in CreateFromDump (MarcoFalke)
fa23ed7fc2 refactor: Use ToIntegral in ParseHDKeypath (MarcoFalke)

Pull request description:

  The legacy int parsing is problematic, because it accepts the `+` sign for unsigned integers. In all cases this is either:

  * Useless, because the `+` sign was already rejected.
  * Erroneous and inconsistent, when third party parsers reject it. (C.f. https://github.com/bitcoin/bitcoin/pull/32365)
  * Confusing, because the `+` sign is  neither documented, nor can it be assumed to be present.

  Fix all issues by removing the legacy int parsing.

ACKs for top commit:
  stickies-v:
    re-ACK faf55fc80b
  brunoerg:
    code review ACK faf55fc80b

Tree-SHA512: a311ab6a58fe02a37741c1800feb3dcfad92377b4bfb61b433b2393f52ba89ef45d00940972b2767b213a3dd7b59e5e35d5b659c586eacdfe4e565a77b12b19f

src/init.cpp

@@ -1151,8 +1151,8 @@ bool CheckHostPortOptions(const ArgsManager& args) {
         "-rpcport",
     }) {
         if (const auto port{args.GetArg(port_option)}) {
-            uint16_t n;
-            if (!ParseUInt16(*port, &n) || n == 0) {
+            const auto n{ToIntegral<uint16_t>(*port)};
+            if (!n || *n == 0) {
                 return InitError(InvalidPortErrMsg(port_option, *port));
             }
         }