misc: fix issues pointed out by msvc (#7316)

* do not move constant variables

* applet_manager: avoid possible use after move

* use constant references where pointed out by msvc

* extra_hid: initialize response

* ValidateSaveState: passing slot separately is not necessary

* common: mark HashCombine as nodiscard

* cityhash: remove use of using namespace std

* Prefix all size_t with std::

done automatically by executing regex replace `([^:0-9a-zA-Z_])size_t([^0-9a-zA-Z_])` -> `$1std::size_t$2`
based on 7d8f115

* shared_memory.cpp: fix log error format

* fix compiling with pch off

src/common/file_util.cpp

@@ -1159,7 +1159,7 @@ std::size_t IOFile::ReadImpl(void* data, std::size_t length, std::size_t data_si
 }
 
 #ifdef _WIN32
-static std::size_t pread(int fd, void* buf, size_t count, uint64_t offset) {
+static std::size_t pread(int fd, void* buf, std::size_t count, uint64_t offset) {
     long unsigned int read_bytes = 0;
     OVERLAPPED overlapped = {0};
     HANDLE file = reinterpret_cast<HANDLE>(_get_osfhandle(fd));