"nvim -es": disable shada #21723

Problem:
`nvim -es` (and `nvim -Es`) is the recommended way to non-interactively
run commands/vimscript. But it enables shada by default, which is
usually not wanted.

Solution:
- Disable shada by default for `nvim -es/-Es`. This can be overridden by
  `-i foo` if needed.
- Do NOT change the 'loadplugins' default.
  - User config + packages _should_ be enabled by default, for both `nvim
    -es` and `nvim -l`. Else any Lua packages you have can't be accessed
    without `-u path/to/config`, which is clumsy.
      - Use-cases:
        ```
        nvim --headless "+Lazy! sync" +qa
            would become: nvim -es "+Lazy! sync"
        nvim --headless +PlugInstall +qall
            would become: nvim -es +PlugInstall
        ```
  - Opt-out (`--clean` or `-u NONE`) is much easier than opt-in (`-u
    path/to/config`).
  -  User config/packages are analogous to pip packages, which are
     expected when doing `python -c ...`.

related: 7c94bcd2d77e2e54b8836ab8325460a367b79eae
related: ddd0eb6f5120a09b97867d2561ea61309038ccd2

1 files changed, 2 insertions, 0 deletions

diff --git a/runtime/doc/vim_diff.txt b/runtime/doc/vim_diff.txt
index 9f28b373ee..a92ddf33e6 100644
--- a/runtime/doc/vim_diff.txt
+++ b/runtime/doc/vim_diff.txt
@@ -409,6 +409,8 @@ Startup:
 - |-es| and |-Es| have improved behavior:
     - Quits automatically, don't need "-c qa!".
     - Skips swap-file dialog.
+    - Optimized for non-interactive scripts: disables swapfile, shada.
+- |-l| Executes Lua scripts non-interactively.
 - |-s| reads Normal commands from stdin if the script name is "-".
 - Reading text (instead of commands) from stdin |--|:
     - works by default: "-" file is optional