util, decode, vi: fix leak variables

- util: esc from ble/util/keyseq2chars
- util: a, b from ble/string#escape-for-bash-specialchars
- decode: qseq1, nseq1 from ble/decode/cmap/.generate-binder-template
- vi: ret from ble/keymap:vi/update-mode-indicator

ble-decode.sh

@@ -1562,8 +1562,8 @@ function ble-decode-bind/cmap/.generate-binder-template {
   for ccode in "${ccodes[@]}"; do
     local ret
     ble-decode-bind/c2dqs "$ccode"
-    qseq1=$qseq$ret
-    nseq1="$nseq $ccode"
+    local qseq1=$qseq$ret
+    local nseq1="$nseq $ccode"
 
     builtin eval "local ent=\${_ble_decode_cmap_$tseq[$ccode]}"
     if [[ ${ent%_} ]]; then