'autocmd BufWritePre * StripWhitespace' breaks 'ToggleStripWhitespaceOnSave'

[docwhat]

autocmd BufWritePre * StripWhitespace doesn't set g:strip_whitespace_on_save to 1. This breaks ToggleStripWhitespaceOnSave because it'll be the default (0).

How to reproduce

1. Put autocmd BufWritePre * StripWhitespace in your .vimrc or .config/nvim/init.vim.
2. Edit a file that isn't in the black list.
3. :ToggleStripWhitespaceOnSave.
4. Add trailing whitespace.
5. Save (:w)

What happened

The whitespace was stripped on save.

What I expected

The whitespace should not be stripped because I toggled it from the default (enabled) state.