fix: workaround for gencompl on macOS 12.3

completion-generator doesn't detect python on systems with only python3
binaries.

macOS 12.3 now no longer has a python executable; python 2.x has been
completely removed.

See: RobSis/zsh-completion-generator#19

Author: docwhat

zsh/startup/z-zinit-env.zsh

@@ -14,6 +14,10 @@ export _ZL_MATCH_MODE=1
 export _ZL_ROOT_MARKERS=".git,.svn,.hg,.root,package.json"
 
 # RobSis/zsh-completion-generator
+if [[ -z $GENCOMPL_PY ]] && [[ -z "${commandds[python]}" ]] && [[ -n "${commands[python3]}" ]]; then
+  # It doesn't auto-detect 'python3' when 'python' is missing.
+  GENCOMPL_PY=python3
+fi
 GENCOMPL_FPATH="${ZSH_CACHE_DIR}/completion-generator"
 
 # EOF