docs: i2c: instantiating-devices: use monospace for sysfs attributes

Use a monospace (literal) formatting for better readability of sysfs
attributes.

Signed-off-by: Luca Ceresoli <[e-mail]>
Reviewed-by: Jean Delvare <[e-mail]>
Signed-off-by: Wolfram Sang <[e-mail]>

Documentation/i2c/instantiating-devices.rst

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 what addresses they live at. However, in certain cases, it does not, so a
 sysfs interface was added to let the user provide the information. This
 interface is made of 2 attribute files which are created in every I2C bus
-directory: new_device and delete_device. Both files are write only and you
-must write the right parameters to them in order to properly instantiate,
-respectively delete, an I2C device.
+directory: ``new_device`` and ``delete_device``. Both files are write
+only and you must write the right parameters to them in order to properly
+instantiate, respectively delete, an I2C device.
 
-File new_device takes 2 parameters: the name of the I2C device (a string)
-and the address of the I2C device (a number, typically expressed in
-hexadecimal starting with 0x, but can also be expressed in decimal.)
+File ``new_device`` takes 2 parameters: the name of the I2C device (a
+string) and the address of the I2C device (a number, typically expressed
+in hexadecimal starting with 0x, but can also be expressed in decimal.)
 
-File delete_device takes a single parameter: the address of the I2C
+File ``delete_device`` takes a single parameter: the address of the I2C
 device. As no two devices can live at the same address on a given I2C
 segment, the address is sufficient to uniquely identify the device to be
 deleted.