vim: Import v8.1.0258

* 8.1.0258: not enough testing for the CompleteDone event
* 8.1.0257: no test for pathshorten()
* 8.1.0256: using setline() in TextChangedI splits undo
* 8.1.0255: backup test fails when using shadow directory

Author: chrisbra

gitlog.txt

@@ -1 +1 @@
-* [8.1.0254](https://github.com/vim/vim/releases/tag/v8.1.0254): cannot build on MS-Windows; unused macro HAVE_HANDLE_DROP\n* [8.1.0253](https://github.com/vim/vim/releases/tag/v8.1.0253): saving and restoring window title does not always work\n* [8.1.0252](https://github.com/vim/vim/releases/tag/v8.1.0252): quickfix functions are too long\n* [8.1.0251](https://github.com/vim/vim/releases/tag/v8.1.0251): using full path is not supported for 'backupdir'\n* [8.1.0250](https://github.com/vim/vim/releases/tag/v8.1.0250): MS-Windows using VTP: windows size change incorrect\n* [8.1.0249](https://github.com/vim/vim/releases/tag/v8.1.0249): GTK: when screen DPI changes Vim does not handle it\n* [8.1.0248](https://github.com/vim/vim/releases/tag/v8.1.0248): duplicated quickfix code\n* [8.1.0247](https://github.com/vim/vim/releases/tag/v8.1.0247): Python: error message for failing import is incorrect\n* [8.1.0246](https://github.com/vim/vim/releases/tag/v8.1.0246): build failure without the +eval feature\n* [8.1.0245](https://github.com/vim/vim/releases/tag/v8.1.0245): calling setline() in TextChangedI autocmd breaks undo\n* [8.1.0244](https://github.com/vim/vim/releases/tag/v8.1.0244): no redraw when using a STOP signal on Vim and then CONT\n* [8.1.0243](https://github.com/vim/vim/releases/tag/v8.1.0243): using :term ++close ++hidden closes a window\n* [8.1.0242](https://github.com/vim/vim/releases/tag/v8.1.0242): Insert mode completion may use an invalid buffer pointer\n* [8.1.0241](https://github.com/vim/vim/releases/tag/v8.1.0241): effect of ":tabmove N" is not clear
+* [8.1.0258](https://github.com/vim/vim/releases/tag/v8.1.0258): not enough testing for the CompleteDone event\n* [8.1.0257](https://github.com/vim/vim/releases/tag/v8.1.0257): no test for pathshorten()\n* [8.1.0256](https://github.com/vim/vim/releases/tag/v8.1.0256): using setline() in TextChangedI splits undo\n* [8.1.0255](https://github.com/vim/vim/releases/tag/v8.1.0255): backup test fails when using shadow directory