.gitconfig

[alias]
    g = !env GIT_PAGER='gawk -f ~/file-alias-pager.awk | less' git grep

.zshrc

function precmd {
    # you might have this already: vcs_info 'prompt'
    source ~/.zsh-file-aliases
}

file-alias-pager.awk

BEGIN {
  file = ENVIRON["HOME"] "/.zsh-file-aliases"
  printf "" > file
}
match($0, /^([^\x1b:]*)[\x1b:].*$/, m) {
  print "alias -g _" ++n "=" m[1] >> file
  printf "\x1b[33m[%2d]\x1b[0m", n
}
{ print }