feat(lua)!: execute Lua with "nvim -l"

Problem:
Nvim has Lua but the "nvim" CLI can't easily be used to execute Lua
scripts, especially scripts that take arguments or produce output.

Solution:
- support "nvim -l [args...]" for running scripts. closes #15749
- exit without +q
- remove lua2dox_filter
- remove Doxyfile. This wasn't used anyway, because the doxygen config
  is inlined in gen_vimdoc.py (`Doxyfile` variable).
- use "nvim -l" in docs-gen CI job

Examples:

    $ nvim -l scripts/lua2dox.lua --help
    Lua2DoX (0.2 20130128)
    ...

    $ echo "print(vim.inspect(_G.arg))" | nvim -l - --arg1 --arg2
    $ echo 'print(vim.inspect(vim.api.nvim_buf_get_text(1,0,0,-1,-1,{})))' | nvim +"put ='text'" -l -

TODO?
  -e executes Lua code
  -l loads a module
  -i enters REPL _after running the other arguments_.

1 files changed, 0 insertions, 90 deletions

diff --git a/scripts/lua2dox_filter b/scripts/lua2dox_filter
deleted file mode 100755
index e3fa95d0cf..0000000000
--- a/scripts/lua2dox_filter
+++ /dev/null
@@ -1,90 +0,0 @@
-#!/usr/bin/env bash
-
-###########################################################################
-#   Copyright (C) 2012 by Simon Dales   #
-#   simon@purrsoft.co.uk   #
-#                                                                         #
-#   This program is free software; you can redistribute it and/or modify  #
-#   it under the terms of the GNU General Public License as published by  #
-#   the Free Software Foundation; either version 2 of the License, or     #
-#   (at your option) any later version.                                   #
-#                                                                         #
-#   This program is distributed in the hope that it will be useful,       #
-#   but WITHOUT ANY WARRANTY; without even the implied warranty of        #
-#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         #
-#   GNU General Public License for more details.                          #
-#                                                                         #
-#   You should have received a copy of the GNU General Public License     #
-#   along with this program; if not, write to the                         #
-#   Free Software Foundation, Inc.,                                       #
-#   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             #
-###########################################################################
-LANG=""
-
-##! \brief test executable to see if it exists
-test_executable() {
-  P_EXE="$1"
-  #########
-  WHICH=$(which "$P_EXE")
-  if test -z "${WHICH}"; then
-    echo "not found \"${P_EXE}\""
-  else
-    EXE="${P_EXE}"
-  fi
-}
-
-##! \brief sets the lua interpreter
-set_lua() {
-  if test -z "${EXE}"; then
-    test_executable '.deps/usr/bin/luajit'
-  fi
-
-  if test -z "${EXE}"; then
-    test_executable 'luajit'
-  fi
-
-  if test -z "${EXE}"; then
-    test_executable 'lua'
-  fi
-}
-
-##! \brief makes canonical name of file
-##!
-##! Note that "readlink -f" doesn't work in MacOSX
-##!
-do_readlink() {
-  pushd . > /dev/null
-  TARGET_FILE=$1
-
-  cd "$(dirname $TARGET_FILE)"
-  TARGET_FILE=$(basename "$TARGET_FILE")
-
-  # Iterate down a (possible) chain of symlinks
-  while [ -L "$TARGET_FILE" ]; do
-    TARGET_FILE=$(readlink "$TARGET_FILE")
-    cd $(dirname "$TARGET_FILE")
-    TARGET_FILE=$(basename "$TARGET_FILE")
-  done
-
-  PHYS_DIR=$(pwd -P)
-  RESULT=$PHYS_DIR
-  popd > /dev/null
-}
-
-##main
-set_lua
-if test -z "${EXE}"; then
-  echo "no lua interpreter found"
-  exit 1
-else
-  BASENAME=$(basename "$0")
-  do_readlink "$0"
-  DIRNAME="${RESULT}"
-
-  LUASCRIPT="${DIRNAME}/lua2dox.lua ${BASENAME}"
-  #echo "lua[${LUASCRIPT}]"
-
-  ${EXE} ${LUASCRIPT} $@
-fi
-
-##eof