Exclude "of" from default AvoidInfix configuration (used in ScalaTest)

[piter75]

Fixes #3699

It also:

• makes the more ScalaTest formatting test a bit more realistic
• uses some arbitrary infix call in excludeFilters list append test

[kitbellew]

@piter75 thank you for this submission. there's an alternative, #3711, which takes a slightly more conservative approach of excluding only behavior.of, as opposed to *.of which might be a little too wide.

[piter75]

@kitbellew The "wideness" of the exclusion crossed my mind but I decided it's ok if we already exclude both in and be.

Anyway, being specific here is much better.

[kitbellew]

@kitbellew The "wideness" of the exclusion crossed my mind but I decided it's ok if we already exclude both in and be.

is there a way to limit in or be?

[piter75]

IMHO be always comes after should or must in assertions but I would have to do some research to be certain

in is used in both FlatSpec and FreeSpec styles which implies that it comes after a String "literal".
Maybe we could narrow it down to " in.
Someone may probably store the preceding string in a variable but that would (most probably) be rare.

Those changes could potentially be backwards incompatible so maybe it's not worth changing it.