Fix table visualization.

Author: jvreca

docs/qonnx-custom-ops/quant_op.md

@@ -49,18 +49,18 @@ This operator is not part of the ONNX standard and is not currently versioned.
 #### Rounding modes
 <details>
 <summary>rounding modes</summary>
-| **Number \ ROUNDING_MODE** 	| ROUND=HALF_EVEN 	| CEIL 	| FLOOR 	| UP 	| DOWN 	| HALF_UP 	| HALF_DOWN 	|
-|----------------------------	|-----------------	|------	|-------	|----	|------	|---------	|-----------	|
-| 5.5                        	| 6               	| 6    	| 5     	| 6  	| 5    	| 6       	| 5         	|
-| 2.5                        	| 2               	| 3    	| 2     	| 3  	| 2    	| 3       	| 2         	|
-| 1.6                        	| 2               	| 2    	| 1     	| 2  	| 1    	| 2       	| 2         	|
-| 1.1                        	| 1               	| 2    	| 1     	| 2  	| 1    	| 1       	| 1         	|
-| 1.0                        	| 1               	| 1    	| 1     	| 1  	| 1    	| 1       	| 1         	|
-| -1.0                       	| -1              	| -1   	| -1    	| -1 	| -1   	| -1      	| -1        	|
-| -1.1                       	| -1              	| -1   	| -2    	| -2 	| -1   	| -1      	| -1        	|
-| -1.6                       	| -2              	| -1   	| -2    	| -2 	| -1   	| -2      	| -2        	|
-| -2.5                       	| -2              	| -2   	| -3    	| -3 	| -2   	| -3      	| -2        	|
-| -5.5                       	| -6              	| -5   	| -6    	| -6 	| -5   	| -6      	| -5        	|
+| **Number \ ROUNDING_MODE** | ROUND=HALF_EVEN | CEIL | FLOOR | UP | DOWN | HALF_UP | HALF_DOWN |
+|----------------------------|-----------------|------|-------|----|------|---------|-----------|
+| 5.5                        | 6               | 6    | 5     | 6  | 5    | 6       | 5         |
+| 2.5                        | 2               | 3    | 2     | 3  | 2    | 3       | 2         |
+| 1.6                        | 2               | 2    | 1     | 2  | 1    | 2       | 2         |
+| 1.1                        | 1               | 2    | 1     | 2  | 1    | 1       | 1         |
+| 1.0                        | 1               | 1    | 1     | 1  | 1    | 1       | 1         |
+| -1.0                       | -1              | -1   | -1    | -1 | -1   | -1      | -1        |
+| -1.1                       | -1              | -1   | -2    | -2 | -1   | -1      | -1        |
+| -1.6                       | -2              | -1   | -2    | -2 | -1   | -2      | -2        |
+| -2.5                       | -2              | -2   | -3    | -3 | -2   | -3      | -2        |
+| -5.5                       | -6              | -5   | -6    | -6 | -5   | -6      | -5        |
 </details>
 
 #### Examples