std.Progress: use *W functions on windows

Closes #534.
See: https://source.winehq.org/git/wine.git/blob/refs/heads/stable:/dlls/kernelbase/console.c#l520

Author: 0x08088405

lib/std/Progress.zig

@@ -234,7 +234,7 @@ fn refreshWithHeldLock(self: *Progress) void {
             self.terminal = null;
             break :winapi;
         }
-        if (windows.kernel32.FillConsoleOutputCharacterA(
+        if (windows.kernel32.FillConsoleOutputCharacterW(
             file.handle,
             ' ',
             fill_chars,

lib/std/os/windows/kernel32.zig

@@ -90,6 +90,7 @@ pub extern "kernel32" fn GetConsoleMode(in_hConsoleHandle: HANDLE, out_lpMode: *
 
 pub extern "kernel32" fn GetConsoleScreenBufferInfo(hConsoleOutput: HANDLE, lpConsoleScreenBufferInfo: *CONSOLE_SCREEN_BUFFER_INFO) callconv(WINAPI) BOOL;
 pub extern "kernel32" fn FillConsoleOutputCharacterA(hConsoleOutput: HANDLE, cCharacter: CHAR, nLength: DWORD, dwWriteCoord: COORD, lpNumberOfCharsWritten: LPDWORD) callconv(WINAPI) BOOL;
+pub extern "kernel32" fn FillConsoleOutputCharacterW(hConsoleOutput: HANDLE, cCharacter: WCHAR, nLength: DWORD, dwWriteCoord: COORD, lpNumberOfCharsWritten: LPDWORD) callconv(WINAPI) BOOL;
 pub extern "kernel32" fn FillConsoleOutputAttribute(hConsoleOutput: HANDLE, wAttribute: WORD, nLength: DWORD, dwWriteCoord: COORD, lpNumberOfAttrsWritten: LPDWORD) callconv(WINAPI) BOOL;
 pub extern "kernel32" fn SetConsoleCursorPosition(hConsoleOutput: HANDLE, dwCursorPosition: COORD) callconv(WINAPI) BOOL;