vim-patch:9.0.1725: cursor pos wrong after concealed text with 'virtualedit'

Problem:    Wrong cursor position when clicking after concealed text
            with 'virtualedit'.
Solution:   Store virtual columns in ScreenCols[] instead of text
            columns, and always use coladvance() when clicking.

This also fixes incorrect curswant when clicking on a TAB, so now
Test_normal_click_on_ctrl_char() asserts the same results as the ones
before patch 9.0.0048.

closes: vim/vim#12808

e500ae8e29

Remove the mouse_adjust_click() function.

There is a difference in behavior with the old mouse_adjust_click()
approach: when clicking on the character immediately after concealed
text that is completely hidden, cursor is put on the clicked character
rather than at the start of the concealed text. The new behavior is
better, but it causes unnecessary scrolling in a functional test (which
is an existing issue unrelated to these patches), so adjust the test.

Now fully merged:
vim-patch:9.0.0177: cursor position wrong with 'virtualedit' and mouse click

src/nvim/grid.h

@@ -27,6 +27,7 @@ EXTERN bool resizing_screen INIT(= 0);
 
 EXTERN schar_T *linebuf_char INIT(= NULL);
 EXTERN sattr_T *linebuf_attr INIT(= NULL);
+EXTERN colnr_T *linebuf_vcol INIT(= NULL);
 
 // Low-level functions to manipulate individual character cells on the
 // screen grid.