bugfix; ArduPilot SRx_ parameters note

[drtrigon]

follow-up to #512

As I came across some FC that had 6 SERIAL but only 4 SR it became kind of obvious that these number don't have to match.

[deadbytefpv]

Maybe explain a bit more as to why they don't match, instead of being vague about why.

IMHO, it's a bit superficial to add the note, when the instruction says to change them all into the same values anyway.

[drtrigon]

The SRx (for some generally unknown 'x') have to be set for mavlink to work over elrs.

The paragraph starts with

Replace x with the UART number you are using.

For me it worked using SERIAL1 and SR1 in one setup but not in another one. Thus I wanted to prevent others to be fooled by this.

I did not find any hint on how to figure out which SRx to use in specific cases.

Saying set all params for all SRx (meaning all 'x') might be a bit extreme.

[deadbytefpv]

Since the note is for Ardu, maybe put it inside the Ardu tab.

(move note and add indents)

[drtrigon]

Good idea!

Can you give me a hint on how to do this as do not have the means to test whether the final redering looks ok.

[deadbytefpv]

Docker should allow you to view the whole site based off your branch.

[drtrigon]

@deadbytefpv : Thanks. Change done. Comments?

[deadbytefpv]

I'll have to check with the others before I make an approval, and/or comment further.