vim-patch:8.2.{3468,3617,3618,3622}: some other CWD related patches

Problem:    getcompletion() always passes zero as position to custom
            completion function.
Solution:   Pass the pattern length. (closes vim/vim#9173)
https://github.com/vim/vim/commit/4785fe02bba14c4e0aede0fa425ca790a1cb98d7

Co-authored-by: ii14 <ii14@users.noreply.github.com>

* sp_enum_after_assign = force
* sp_brace_typedef = force
* nl_do_brace = remove
* sp_do_brace_open = force
* sp_brace_close_while = force
* sp_before_semi = remove
* sp_before_semi_for = remove
* sp_before_semi_for_empty = remove
* sp_between_semi_for_empty = remove
* sp_after_semi_for_empty = remove
* sp_before_square = remove
* sp_before_squares = remove
* sp_inside_square = remove
* sp_inside_fparens = remove
* sp_inside_fparen = remove
* sp_inside_tparen = remove
* sp_after_tparen_close = remove
* sp_return_paren = force
* pos_bool = lead
* sp_pp_concat = remove
* sp_pp_stringify = remove
* fixup: disable formatting for the INIT section

* fix(eval): fixup for empty modifier in fnamemodify

https://github.com/neovim/neovim/commit/1dbbaf89bf5d3bcd1edac3af9938c2e2dd18f816
erroneously removed a check for empty modifier and a PVS fix. 
Restore that check and fix.

Fixes #16367

Co-authored-by: zeertzjq <zeertzjq@outlook.com>

Problem:    getcwd() is unclear about how 'autochdir' is used.
Solution:   Update the help for getcwd().  Without any arguments always return
            the actual current directory. (closes vim/vim#9142)
https://github.com/vim/vim/commit/851c7a699ae00bdc14a4db874cf722b7b7393b53

* refactor: reduce number of explicit char casts

clean up docs for MB_PTR_ADV and MB_PTR_BACK

Problem:    Argument for message functions is inconsistent.
Solution:   Make first argument to msg() "char *".
https://github.com/vim/vim/commit/32526b3c1846025f0e655f41efd4e5428da16b6c