Documentation: ad4130: format list of in_voltage-voltage_filter_mode_available modes

Sphinx reports two warnings on sysfs documentation for AD4130 driver:

Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130:2: WARNING: Unexpected indentation.
Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130:2: WARNING: Block quote ends without a blank line; unexpected unindent.

These are due to misformatting of sinc* modes list. Format it with bullet
list. Since each entry spans multiple lines, separate each with a blank
line.

Fixes: 62094060 ("iio: adc: ad4130: add AD4130 driver")
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://lore.kernel.org/r/20221106140233.74112-1-bagasdotme@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Documentation/ABI/testing/sysfs-bus-iio-adc-ad4130

@@ -3,25 +3,35 @@ KernelVersion:  6.2
 Contact:	linux-iio@vger.kernel.org
 Description:
 		Reading returns a list with the possible filter modes.
-		"sinc4"       - Sinc 4. Excellent noise performance. Long 1st
-				conversion time. No natural 50/60Hz rejection.
-		"sinc4+sinc1" - Sinc4 + averaging by 8. Low 1st conversion time.
-		"sinc3"	      - Sinc3. Moderate 1st conversion time. Good noise
-				performance.
-		"sinc3+rej60" - Sinc3 + 60Hz rejection. At a sampling frequency
-				of 50Hz, achieves simultaneous 50Hz and 60Hz
-				rejection.
-		"sinc3+sinc1" - Sinc3 + averaging by 8. Low 1st conversion time.
-				Best used with a sampling frequency of at least
-				216.19Hz.
-		"sinc3+pf1"   - Sinc3 + Post Filter 1.
-				53dB rejection @ 50Hz, 58dB rejection @ 60Hz.
-		"sinc3+pf2"   - Sinc3 + Post Filter 2.
-				70dB rejection @ 50Hz, 70dB rejection @ 60Hz.
-		"sinc3+pf3"   - Sinc3 + Post Filter 3.
-				99dB rejection @ 50Hz, 103dB rejection @ 60Hz.
-		"sinc3+pf4"   - Sinc3 + Post Filter 4.
-				103dB rejection @ 50Hz, 109dB rejection @ 60Hz.
+
+		  * "sinc4"       - Sinc 4. Excellent noise performance. Long
+                    1st conversion time. No natural 50/60Hz rejection.
+
+		  * "sinc4+sinc1" - Sinc4 + averaging by 8. Low 1st conversion
+		    time.
+
+		  * "sinc3"	      - Sinc3. Moderate 1st conversion time.
+		    Good noise performance.
+
+		  * "sinc3+rej60" - Sinc3 + 60Hz rejection. At a sampling
+		    frequency of 50Hz, achieves simultaneous 50Hz and 60Hz
+		    rejection.
+
+		  * "sinc3+sinc1" - Sinc3 + averaging by 8. Low 1st conversion
+		    time. Best used with a sampling frequency of at least
+		    216.19Hz.
+
+		  * "sinc3+pf1"   - Sinc3 + Post Filter 1. 53dB rejection @
+		    50Hz, 58dB rejection @ 60Hz.
+
+		  * "sinc3+pf2"   - Sinc3 + Post Filter 2. 70dB rejection @
+		    50Hz, 70dB rejection @ 60Hz.
+
+		  * "sinc3+pf3"   - Sinc3 + Post Filter 3. 99dB rejection @
+		    50Hz, 103dB rejection @ 60Hz.
+
+		  * "sinc3+pf4"   - Sinc3 + Post Filter 4. 103dB rejection @
+		    50Hz, 109dB rejection @ 60Hz.
 
 What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY-voltageZ_filter_mode
 KernelVersion:  6.2