Problem:    Vim9: allowing use of "s:" leads to inconsistencies.
Solution:   Disallow using "s:" in Vim9 script at the script level.

Problem:    crash when repeatedly using :retab.
Solution:   Bail out when the line is getting too long.

Problem:    Vim9: line number of exception is not set.
Solution:   Set the line number before throwing an exception. (closes #9755)

Problem:    sticky command modifiers are too sticky.
Solution:   Do not apply command modifiers to a sourced script. (closes #9751)

Problem:    Command line completion functions are very long.
Solution:   Refactor into multiple functions. (Yegappan Lakshmanan,
            closes #9753)

Problem:    Unnecessary call to check_colorcolumn().
Solution:   Remove the call. (Sean Dewar, closes #9748)

Problem:    Dynamic loading of libsodium not handled properly.
Solution:   Fix has() and :version. Show an error message when loading fails.
            Fix memory leaks. (Ken Takata, closes #9754)

Problem:    CI does not use the latest Lua and Python.
Solution:   Use Lua 5.4.2 and Python 3.10. (closes #9744)

Problem:    ReScript files are not recognized.
Solution:   Add the *.res and *.resi patterns. (Ananda Umamil, closes #9752)

Problem:    No coverage is measured on MS-Windows CI.
Solution:   Enable coverage on MS-Windows. (Ozaki Kiichi, closes #9750)