Problem:    The eval.c file is too big.
Solution:   Move code related to variables to evalvars.c. (Yegappan
            Lakshmanan, closes #4868)

Problem:    Ml_get errors after using append(). (Alex Genco)
Solution:   Do not update the cursor twice. (closes #1737)

Problem:    Syntax test fails.
Solution:   Add new javascriptreact type to completions.

Problem:    Cannot recognize .jsx and .tsx files.
Solution:   Recognize them as javascriptreact and typescriptreact.
            (closes #4830)

Problem:    No tests for text property popup window.
Solution:   Add a few tests.

Problem:    Popup windows don't move with the text when making changes.
Solution:   Add the 'textprop" property to the popup window options, position
            the popup relative to a text property. (closes #4560)
            No tests yet.

Problem:    Code for dealing with script files is spread out.
Solution:   Move the code to scriptfile.c. (Yegappan Lakshmanan, closes #4861)

Problem:    Cursorline not redrawn when putting a line above the cursor.
Solution:   Redraw when the curor line is below a change. (closes #4862)

Problem:    More functions can be used as methods.
Solution:   Make various functions usable as a method.

Problem:    Using empty string for current buffer is unexpected.
Solution:   Make the argument optional for bufname() and bufnr().