register_shim() already deduplicates via associative array (bash 4+) or
by checking if a shim already exists (bash 3.2). The sort -u pipe in the make_shims
call is thus redundant -- the dedup happens downstream regardless. Shim
creation is order-independent and idempotent, so sorting has no semantic
effect either.
Saves one subprocess fork during every rehash invocation.
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