Problem:    An empty change is reported to a listener.
Solution:   Do not report an empty change. (closes #9768)  Remove unused
            return value.

Problem:    Incsearch highlight broken when calling searchcount() in 'tabLine'
            function. (Mirko Palmer)
Solution:   Save and restore the incsearch state. (Christian Brabandt,
            closes #9763, closes #9633)

Problem:    CI steps for Windows are a bit unorganized.
Solution:   Organize CI test steps on Windows. (Ozaki Kiichi, closes #9764)

Problem:    Not enough tests for command line completion.
Solution:   Add a few more tests. (Yegappan Lakshmanan, closes #9771)

Problem:    ctx_imports is not used.
Solution:   Delete ctx_imports.  Add missing dependency.

Problem:    Unreachable code.
Solution:   Remove outdated code lines.

Problem:    Expression test fails.
Solution:   Make the test work with latest Vim9 syntax.

Problem:    Filetype detection from file contents is in legacy script.
Solution:   Use a compiled function for filetype detection.

Problem:    Vim9: can create a script variable from a legacy function.
Solution:   Disallow creating a script variable from a function.

Problem:    MS-Windows: libsodium.dll not included with the installer.
Solution:   Add the file to the installer if it exists. (Christian Brabandt,
            closes #9762)