i2c: gpio: fault-injector: better SPHINX style in docs

We don't use SPHINX currently in I2C documentation; but preparing the
I2C fault injector docs already is a good idea since it makes it easier
to read. Especially as new stuff is going to be added soon.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

Documentation/i2c/gpio-fault-injection

+=========================
 Linux I2C fault injection
 =========================
 
@@ -13,6 +14,9 @@ mounted at /sys/kernel/debug. There will be a separate subdirectory per GPIO
 driven I2C bus. Each subdirectory will contain files to trigger the fault
 injection. They will be described now along with their intended use-cases.
 
+Wire states
+===========
+
 "scl"
 -----
 
@@ -34,10 +38,10 @@ I2C specification version 4, section 3.1.16) using the helpers of the Linux I2C
 core (see 'struct bus_recovery_info'). However, the bus recovery will not
 succeed because SDA is still pinned low until you manually release it again
 with "echo 1 > sda". A test with an automatic release can be done with the
-following class of fault injectors.
+"incomplete transfers" class of fault injectors.
 
-Introduction to incomplete transfers
-------------------------------------
+Incomplete transfers
+====================
 
 The following fault injectors create situations where SDA will be held low by a
 device. Bus recovery should be able to fix these situations. But please note: