Added/modified documentation for function arguments.

diff --git a/windows/class.c b/windows/class.c
index 2ea1161..c4c467e 100644
--- a/windows/class.c
+++ b/windows/class.c
@@ -461,7 +461,7 @@
  *	>0: Unique identifier
  *	0: Failure
  */
-ATOM WINAPI RegisterClassA( const WNDCLASSA* wc ) /* Address of structure with class data */
+ATOM WINAPI RegisterClassA( const WNDCLASSA* wc ) /* [in] Address of structure with class data */
 {
     ATOM atom;
     int iSmIconWidth, iSmIconHeight;
diff --git a/windows/cursoricon.c b/windows/cursoricon.c
index f3d4d7f..e52adea 100644
--- a/windows/cursoricon.c
+++ b/windows/cursoricon.c
@@ -1379,7 +1379,7 @@
  *	A handle to the previous cursor shape.
  */
 HCURSOR WINAPI SetCursor(
-	         HCURSOR hCursor /* Handle of cursor to show */
+	         HCURSOR hCursor /* [in] Handle of cursor to show */
 ) {
     HCURSOR hOldCursor;
 
diff --git a/windows/dce.c b/windows/dce.c
index f9b2df5..0f0215e 100644
--- a/windows/dce.c
+++ b/windows/dce.c
@@ -905,7 +905,7 @@
  *	NULL: Failure
  */
 HDC WINAPI GetDC(
-	     HWND hwnd /* handle of window */
+	     HWND hwnd /* [in] handle of window */
 ) {
     if (!hwnd)
         return GetDCEx( GetDesktopWindow(), 0, DCX_CACHE | DCX_WINDOW );
@@ -950,8 +950,8 @@
  *	0: Failure
  */
 INT WINAPI ReleaseDC( 
-             HWND hwnd /* Handle of window - ignored */, 
-             HDC hdc   /* Handle of device context */
+             HWND hwnd /* [in] Handle of window - ignored */, 
+             HDC hdc   /* [in] Handle of device context */
 ) {
     DCE * dce;
     INT nRet = 0;
diff --git a/windows/hook.c b/windows/hook.c
index dc6f0dc..9f3ace1 100644
--- a/windows/hook.c
+++ b/windows/hook.c
@@ -1436,8 +1436,7 @@
 
 /***********************************************************************
  *           CallMsgFilterA   (USER32.15)
- */
-/*
+ *
  * FIXME: There are ANSI and UNICODE versions of this, plus an unspecified
  * version, plus USER (the 16bit one) has a CallMsgFilter32 function.
  */
diff --git a/windows/keyboard.c b/windows/keyboard.c
index 0de7582..bcee740 100644
--- a/windows/keyboard.c
+++ b/windows/keyboard.c
@@ -69,6 +69,8 @@
   initDone = TRUE;
 }
 
+/**********************************************************************/
+
 static VOID WINAPI KEYBOARD_CallKeybdEventProc( FARPROC16 proc,
                                                 BYTE bVk, BYTE bScan,
                                                 DWORD dwFlags, DWORD dwExtraInfo )
@@ -86,6 +88,8 @@
     wine_call_to_16_regs_short( &context, 0 );
 }
 
+/**********************************************************************/
+
 VOID WINAPI WIN16_KEYBOARD_Enable( FARPROC16 proc, LPBYTE lpKeyState )
 {
     LPKEYBD_EVENT_PROC thunk = 
@@ -159,8 +163,8 @@
 
 /**********************************************************************
  *    	VkKeyScan			[KEYBOARD.129]
- */
-/* VkKeyScan translates an ANSI character to a virtual-key and shift code
+ *
+ * VkKeyScan translates an ANSI character to a virtual-key and shift code
  * for the current keyboard.
  * high-order byte yields :
  *	0	Unshifted
diff --git a/windows/message.c b/windows/message.c
index 3255edc..12cb762 100644
--- a/windows/message.c
+++ b/windows/message.c
@@ -1461,11 +1461,11 @@
  *
  */
 BOOL WINAPI PeekMessageW( 
-  LPMSG lpmsg,    /* buffer to receive message */
-  HWND hwnd,      /* restrict to messages for hwnd */
-  UINT min,       /* minimum message to receive */
-  UINT max,       /* maximum message to receive */
-  UINT wRemoveMsg /* removal flags */ 
+  LPMSG lpmsg,    /* [out] buffer to receive message */
+  HWND hwnd,      /* [in] restrict to messages for hwnd */
+  UINT min,       /* [in] minimum message to receive */
+  UINT max,       /* [in] maximum message to receive */
+  UINT wRemoveMsg /* [in] removal flags */ 
 ) 
 {
     BOOL ret = MSG_PeekMessage( QMSG_WIN32W, lpmsg, hwnd, min, max, wRemoveMsg, TRUE );
@@ -1554,10 +1554,10 @@
  * 
  */
 BOOL WINAPI GetMessageW(
-  MSG* lpmsg, /* buffer to receive message */
-  HWND hwnd,  /* restrict to messages for hwnd */
-  UINT min,   /* minimum message to receive */
-  UINT max    /* maximum message to receive */
+  MSG* lpmsg, /* [out] buffer to receive message */
+  HWND hwnd,  /* [in] restrict to messages for hwnd */
+  UINT min,   /* [in] minimum message to receive */
+  UINT max    /* [in] maximum message to receive */
 ) 
 {
     MSG_PeekMessage( QMSG_WIN32W, lpmsg, hwnd, min, max, PM_REMOVE, FALSE );
@@ -1871,12 +1871,12 @@
  *  ECMA-234, Win32 
  */
 LRESULT WINAPI SendMessageW( 
-  HWND hwnd,    /* Window to send message to. If HWND_BROADCAST, 
-                 the message will be sent to all top-level windows. */
+  HWND hwnd,     /* [in] Window to send message to. If HWND_BROADCAST, 
+                         the message will be sent to all top-level windows. */
 
-  UINT msg,      /* message */
-  WPARAM wParam, /* message parameter */
-  LPARAM lParam    /* additional message parameter */
+  UINT msg,      /* [in] message */
+  WPARAM wParam, /* [in] message parameter */
+  LPARAM lParam  /* [in] additional message parameter */
 ) {
     LRESULT res;
 
diff --git a/windows/win.c b/windows/win.c
index 60569e1..bfe006f 100644
--- a/windows/win.c
+++ b/windows/win.c
@@ -2187,9 +2187,9 @@
  *
  */
 LONG WINAPI SetWindowLongW( 
-    HWND hwnd, /* window to alter */
-    INT offset, /* offset, in bytes, of location to alter */
-    LONG newval  /* new value of location */
+    HWND hwnd,  /* [in] window to alter */
+    INT offset, /* [in] offset, in bytes, of location to alter */
+    LONG newval /* [in] new value of location */
 ) {
     return WIN_SetWindowLong( hwnd, offset, newval, WIN_PROC_32W );
 }
diff --git a/windows/winproc.c b/windows/winproc.c
index e74f34b..74635b1 100644
--- a/windows/winproc.c
+++ b/windows/winproc.c
@@ -2527,11 +2527,11 @@
  *   ECMA-234, Win32 
  */
 LRESULT WINAPI CallWindowProcA( 
-    WNDPROC func, /* window procedure */
-    HWND hwnd, /* target window */
-    UINT msg,  /* message */
-    WPARAM wParam, /* message dependent parameter */
-    LPARAM lParam    /* message dependent parameter */
+    WNDPROC func,  /* [in] window procedure */
+    HWND hwnd,     /* [in] target window */
+    UINT msg,      /* [in] message */
+    WPARAM wParam, /* [in] message dependent parameter */
+    LPARAM lParam  /* [in] message dependent parameter */
 ) {
     WINDOWPROC *proc = WINPROC_GetPtr( (WNDPROC16)func );