Editorial: Consistify re "elements in/of"

[jmdyck]

The spec is inconsistent on "element[s] in X" vs "element[s] of X".

In pseudocode, I count 37 "in" vs 229 "of".

So in the first commit, I change all the "in" to "of".

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However, I don't entirely like the result. While:

• "the elements of X"
• "each element of X"
• "an element of X"
• "the first/last element of X"

all sound fine to me, "the number of elements of X" sounds odd.

Compare:

• "the number of hours in a day" vs "the number of hours of a day"
• "the number of pups in a litter" vs "the number of pups of a litter"

Also note that the status quo spec has

• ~28 occurrences of "the number of elements in" vs
• ~11 of "the number of elements of".

So in the second commit, I change "of" to "in" just for "the number of elements of X".

(Alternatively, we could avoid this question by instead using the phrase "the length of X". Currently we only use that for Strings.)

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The net effect of the 2 commits is:

• 11x "the number of elements of X" -> "the number of elements in X"
• 1x "the elements in the List X" -> "the elements of the List X"
• 2x "the last element in X" -> "the last element of X"
• 6x "the element in X" -> "the element of X"

I've left it as two commits in case you want to look at the effect of just the first.

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Historical note: PR #2152 standardized on "of" for iteration: "For each element foo of X".