Documentation: irq/concepts: Add commas and reflow

For easier reading, it is always desired to add commas at some places in
text. Like before adverbs or after fronted sentences.

[ tglx: Fix up subject prefix ]

Signed-off-by: Jiri Slaby (SUSE) <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]

Documentation/core-api/irq/concepts.rst

···
 What is an IRQ?
 ===============
 
-An IRQ is an interrupt request from a device.
-Currently they can come in over a pin, or over a packet.
-Several devices may be connected to the same pin thus
-sharing an IRQ.
+An IRQ is an interrupt request from a device. Currently, they can come
+in over a pin, or over a packet. Several devices may be connected to
+the same pin thus sharing an IRQ.
 
 An IRQ number is a kernel identifier used to talk about a hardware
-interrupt source.  Typically this is an index into the global irq_desc
-array, but except for what linux/interrupt.h implements the details
+interrupt source. Typically, this is an index into the global irq_desc
+array, but except for what linux/interrupt.h implements, the details
 are architecture specific.
 
 An IRQ number is an enumeration of the possible interrupt sources on a
-machine.  Typically what is enumerated is the number of input pins on
-all of the interrupt controller in the system.  In the case of ISA
+machine. Typically, what is enumerated is the number of input pins on
+all of the interrupt controllers in the system. In the case of ISA,
 what is enumerated are the 16 input pins on the two i8259 interrupt
 controllers.
 
 Architectures can assign additional meaning to the IRQ numbers, and
-are encouraged to in the case  where there is any manual configuration
-of the hardware involved.  The ISA IRQs are a classic example of
+are encouraged to in the case where there is any manual configuration
+of the hardware involved. The ISA IRQs are a classic example of
 assigning this kind of additional meaning.