clang-tidy: Add performance-faster-string-find check

https://clang.llvm.org/extra/clang-tidy/checks/performance/faster-string-find.html

src/.clang-tidy

@@ -5,6 +5,7 @@ bugprone-use-after-move,
 misc-unused-using-decls,
 modernize-use-default-member-init,
 modernize-use-nullptr,
+performance-faster-string-find,
 performance-for-range-copy,
 performance-move-const-arg,
 performance-no-automatic-move,

src/rpc/util.cpp

@@ -732,12 +732,12 @@ UniValue RPCArg::MatchesType(const UniValue& request) const
 
 std::string RPCArg::GetFirstName() const
 {
-    return m_names.substr(0, m_names.find("|"));
+    return m_names.substr(0, m_names.find('|'));
 }
 
 std::string RPCArg::GetName() const
 {
-    CHECK_NONFATAL(std::string::npos == m_names.find("|"));
+    CHECK_NONFATAL(std::string::npos == m_names.find('|'));
     return m_names;
 }
 

src/util/bip32.cpp

@@ -25,7 +25,7 @@ bool ParseHDKeypath(const std::string& keypath_str, std::vector<uint32_t>& keypa
         }
         // Finds whether it is hardened
         uint32_t path = 0;
-        size_t pos = item.find("'");
+        size_t pos = item.find('\'');
         if (pos != std::string::npos) {
             // The hardened tick can only be in the last index of the string
             if (pos != item.size() - 1) {

src/zmq/zmqpublishnotifier.cpp

@@ -96,7 +96,7 @@ static bool IsZMQAddressIPV6(const std::string &zmq_address)
 {
     const std::string tcp_prefix = "tcp://";
     const size_t tcp_index = zmq_address.rfind(tcp_prefix);
-    const size_t colon_index = zmq_address.rfind(":");
+    const size_t colon_index = zmq_address.rfind(':');
     if (tcp_index == 0 && colon_index != std::string::npos) {
         const std::string ip = zmq_address.substr(tcp_prefix.length(), colon_index - tcp_prefix.length());
         CNetAddr addr;