Fix remaining typos (#7921)

* Fix remaining typos

Found via `codespell -q 3 -S *.hex,*.pdf,./src/libm,./src/hidapi,./src/stdlib/SDL_malloc.c,./src/video/x11/edid.h -L caf,currenty,datas,einstance,fo,hda,lod,mata,parm,parms,pevent,pevents,pixelx,requestor,ser,statics,te,texturers,thid,uscaled,windowz`

src/thread/stdcpp/SDL_systhread.cpp

@@ -69,7 +69,7 @@ SDL_ThreadID(void)
 #ifdef __WINRT__
     return GetCurrentThreadId();
 #else
-    // HACK: Mimick a thread ID, if one isn't otherwise available.
+    // HACK: Mimic a thread ID, if one isn't otherwise available.
     static thread_local SDL_threadID current_thread_id = 0;
     static SDL_threadID next_thread_id = 1;
     static std::mutex next_thread_id_mutex;

src/thread/vita/SDL_systhread.c

@@ -74,7 +74,7 @@ int SDL_SYS_CreateThread(SDL_Thread *thread)
         ThreadEntry, // function to run
         0,           // priority. 0 means priority of calling thread
         stack_size,  // stack size
-        0,           // attibutes. always 0
+        0,           // attributes. always 0
         0,           // cpu affinity mask. 0 = all CPUs
         NULL         // opt. always NULL
     );