This marks the following Vim patches as ported:
vim-patch:8.1.1785: map functionality mixed with character input
Problem: Map functionality mixed with character input.
Solution: Move the map functionality to a separate file. (Yegappan
Lakshmanan, closesvim/vim#4740) Graduate the +localmap feature.
https://github.com/vim/vim/commit/b66bab381c8ba71fd6e92327d1d34c6f8a65f2a7
vim-patch:8.2.3643: header for source file is outdated
Problem: Header for source file is outdated.
Solution: Make the header more accurate. (closesvim/vim#9186)
https://github.com/vim/vim/commit/a3f83feb63eae5464a620ae793c002eb45f7a838
Also cherry-pick a change for <unique> mappings from patch 8.2.0807.
Rename map_clear_mode() to do_mapclear().