Fix: resolved bug where a local keys array in -ftb-compadd shadowed…

[alberti42]

Fix associative subscript completion broken by local keys shadowing

This PR fixes a long‑standing completion bug in fzf-tab where associative array subscripts could complete to unrelated tokens like PREFIX, even when those are not real keys.

Root cause

Inside -ftb-compadd, we declared a local array named keys to capture metadata fields (PREFIX, SUFFIX, IPREFIX, ISUFFIX, etc.) for fzf-tab’s internal completion capture.

However, Zsh’s associative subscript completion uses compadd -a keys and expects a keys array from the completer context (containing the actual associative keys). Because -ftb-compadd runs in the same dynamic scope, our local keys shadowed that array. As a result, completion candidates were taken from our internal metadata list, not the real associative keys.

Symptom

Example (no _approximate needed):

typeset -A ZINIT
ZINIT[PLUGIN_DIR]=/tmp/plugin
ZINIT[PLUGINS_DIR]=/tmp/plugins

# Pressing TAB here could insert PREFIX (not a real key):
echo $ZINIT[P<TAB>

Instead of completing to PLUGIN..., it could insert PREFIX because that was one of the internal metadata field names.

Fix

Rename the internal array from keys to _ftb_compcap_keys in -ftb-compadd to avoid the name collision. This restores correct associative key completion without changing any completion logic or behavior for other paths.

Compatibility

All existing tests continue to pass.