[S] Change in flashrom[main]: Add documentation for pico-serprog

[J. Neuschäfer (Code Review)]

Attention is currently required from: Anastasia Klimchuk, Riku Viitanen, Sydney, Thomas Heijligen.

J. Neuschäfer has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/82229?usp=email )

Change subject: Add documentation for pico-serprog
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Patch Set 1:

(3 comments)

Patchset:

PS1: 
Hi, thanks for writing this :)

File doc/supported_hw/supported_prog/serprog/overview.rst:

https://review.coreboot.org/c/flashrom/+/82229/comment/6f05c81c_b33c3dfa :
PS1, Line 90:  is an bigger existing 
1. typo, → "a bigger"
2. I think this phrase is a bit difficult to understand in english: I had to read it twice, because my first interpretation was that Riku_V's fork was bigger (in some way) than stacksmashing's version.

https://review.coreboot.org/c/flashrom/+/82229/comment/017bb140_b1721be0 :
PS1, Line 91: Notable differences are:
To make this paragraph easier to extend, and perhaps also easier to read, I'd reorganize it a bit:
> pico-serprog is a firmware ....
>
> Notable forks:
> Riku_V's fork uses the hardware SPI implementation ...

The advantages are:

- Every subsection only talks about one thing
- Additional forks are easier to add without rewriting the text, should that become necessary, because there won't be a subsection that tries to present *all* the differences