Input: fix the input_event struct documentation

Fix the datatype of the value field of the input_event struct which is
signed instead of unsigned.

Signed-off-by: Maud Spierings <maud_spierings@hotmail.com>
Link: https://lore.kernel.org/r/20241110-fix_input_doc-v1-1-745d5f908e61@hotmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: SpieringsAE

Documentation/input/input.rst

@@ -264,7 +264,7 @@ events on a read. Their layout is::
 	    struct timeval time;
 	    unsigned short type;
 	    unsigned short code;
-	    unsigned int value;
+	    int value;
     };
 
 ``time`` is the timestamp, it returns the time at which the event happened.