Rename some unicode functions and document better

luprex/cpp/drv/driver-linux.cpp

@@ -221,7 +221,7 @@ static int socket_poll(struct pollfd *pollvec, int pollcount, int mstimeout, std
 
 // Write unicode onto the console.
 static void console_write(const std::u32string &cps) {
-    std::string utf8 = drvutil::to_utf8(cps);
+    std::string utf8 = drvutil::utf32_to_utf8(cps);
     write(1, utf8.c_str(), utf8.size());
 }
 
@@ -231,7 +231,7 @@ static std::u32string console_read() {
     int nread = read(0, buffer, 512);
     if (nread > 0) {
         std::string_view s(buffer, nread);
-        result = drvutil::from_utf8(s, nullptr);
+        result = drvutil::utf8_to_utf32(s, nullptr);
     }
     return result;
 }