Maintenance release to fix issues found in v0.3.4.

FIXES:

f891131c6bb2 #9894 options: properly reset directories on 'autochdir'
9a5488c2a67e Remove MSVC optimization workaround for SHM_ALL
1793ba81762f Make SHM_ALL to a variable instead of a compound literal #define
947069ba1438 doc: mention "pynvim" module rename
46c7e12f27f1 #9629 screen: don't crash when drawing popupmenu with 'rightleft' option
f1843c003576 vim-patch:8.1.0677: look-behind match may use the wrong line number
120442188872 #8325 :terminal : set topline based on window height
aaa8c3d7112a #9504 :recover : Fix crash on non-existent *.swp

Fixes https://github.com/neovim/neovim/issues/9892

gcc-9 has [improved compliance] with the C spec for lifetime of compound
literals, tying their lifetime to block scope instead of function scope.
This makes the behavior comparable to all other automatic variables.

Using the SHM_ALL #define instantiated a compound literal local to an if
clause and assigned the address to a "char_u *".  Since the pointer was
then being used outside of the if clause, it was using an invalid
address.

[improved compliance]: https://gcc.gnu.org/gcc-9/porting_to.html#complit

Closes #9855

closes #9764

screen: don't crash when drawing popupmenu with 'rightleft' option

crash reported in #9584

Problem:    Look-behind match may use the wrong line number. (Dominique Pelle)
Solution:   Use the line number in regsave instead of the one in behind_pos,
            we may be looking at the previous line. (closes vim/vim#3749)
https://github.com/vim/vim/commit/866f3558141aa68862aa2fedbb7747bf2365e838

Reverts d2944e6a298e. mf_open() _can_ fail if the file does not exist.

closes #9503
closes #9504