Problem:    Display wrong when moving cursor to above the top line and
            'smoothscroll' is set.
Solution:   Call adjust_skipcol() in more places and make it work better.
            (Luuk van Baal, closes #12395)

Problem:    Function argument types not always checked and using v:none may
            cause an error.
Solution:   Check argument types once the function type is known.  Do not give
            an error for using v:none as an argument. (closes #12200)

Problem:    Wrong error for unreachable code after :throw.
Solution:   Adjust the error message.

Problem:    Test failures for unreachable code.
Solution:   Add a test override to ignore unreachable code.

Problem:    Vim9: error for missing "return" after "throw".
Solution:   Set had_return flag for "throw". (closes #12262)

Problem:    setcharsearch() does not clear last searched char properly.
Solution:   Do not accept lastc_bytelen smaller than one. (closes #12398)

Problem:    Position of marker for 'smoothscroll' not computed correctly.
Solution:   Take 'list' and other options into account. (Luuk van Baal,
            closes #12393)

Problem:    In cmdline window S-Tab does not select previous completion.
            (Maxim Kim)
Solution:   Add a mappint for S-Tab. (closes #12116)

Problem:    USD filetype is not recognized.
Solution:   Add patterns for USD filetype. (Colin Kennedy, closes #12370)

Problem:    Some commands for opening a file don't use 'switchbuf'.
Solution:   Use 'switchbuf' for more commands. (Yegappan Lakshmanan,
            closes #12383, closes #12381)