docs: fix incorrect example in ?vec_duplicate

[LeonidasZhak]

docs: fix incorrect example in ?vec_duplicate

The example for equivalence with duplicated() used == instead of !=.
vec_duplicate_id(x) == seq_along(x) returns TRUE for first occurrences,
while duplicated(x) returns TRUE for duplicates (not first occurrences).

Fixes #1822.

Summary

Fix the example in ?vec_duplicate that claims to show equivalence with duplicated().

The example used vec_duplicate_id(x) == seq_along(x) but this returns TRUE for first occurrences (i.e., non-duplicates), while duplicated(x) returns TRUE for duplicates. The correct comparison is !=.

Changes

• R/dictionary.R: Change == to != in the example comment
• man/vec_duplicate.Rd: Regenerated from roxygen

Verification

library(vctrs)
x <- c(10, 10, 20, 30, 30, 40)
all.equal(vec_duplicate_id(x) != seq_along(x), duplicated(x))
#> TRUE

Fixes #1822.

[DavisVaughan]

Assuming this is the same as tidymodels/broom#1281 (comment)