patch 9.0.0439: cursor wrong if inserting before line with virtual text above

Problem:    Cursor wrong if inserting before line with virtual text above.
Solution:   Add the width of the "above" virtual text to the cursor position.
            (issue #11084)

src/charset.c

@@ -1576,6 +1576,9 @@ getvcol(
 	    if (((State & MODE_INSERT) == 0 || cts.cts_start_incl) && !on_NUL)
 		// cursor is after inserted text, unless on the NUL
 		vcol += cts.cts_cur_text_width;
+	    else
+		// insertion also happens after the "above" virtual text
+		vcol += cts.cts_first_char;
 #endif
 	    *cursor = vcol + head;	    // cursor at start
 	}

src/testdir/dumps/Test_prop_with_text_above_2.dump

@@ -0,0 +1,9 @@
+|f+0&#ffff4012|i|r|s|t| |t|h|i|n|g| |a|b|o|v|e| @42
+|s+0&#ffd7ff255|e|c|o|n|d| |t|h|i|n|g| |a|b|o|v|e| @41
+>o+0&#ffffff0|n|e| |t|w|o| @52
+|t|h|r|e@1| |f|o|u|r| @49
+|a+0&#ffff4012|n|o|t|h|e|r| |t|h|i|n|g| @46
+|f+0&#ffffff0|i|v|e| |s|i|x| @51
+|~+0#4040ff13&| @58
+|~| @58
+|-+2#0000000&@1| |I|N|S|E|R|T| |-@1| +0&&@29|1|,|1|-|1|2|1| @6|A|l@1| 

src/testdir/dumps/Test_prop_with_text_above_3.dump

@@ -0,0 +1,9 @@
+|f+0&#ffff4012|i|r|s|t| |t|h|i|n|g| |a|b|o|v|e| @42
+|s+0&#ffd7ff255|e|c|o|n|d| |t|h|i|n|g| |a|b|o|v|e| @41
+|i+0&#ffffff0|n|s|e|r|t|e|d> |o|n|e| |t|w|o| @43
+|t|h|r|e@1| |f|o|u|r| @49
+|a+0&#ffff4012|n|o|t|h|e|r| |t|h|i|n|g| @46
+|f+0&#ffffff0|i|v|e| |s|i|x| @51
+|~+0#4040ff13&| @58
+|~| @58
+| +0#0000000&@41|1|,|9|-|1|2|9| @6|A|l@1| 

src/testdir/test_textprop.vim

@@ -2865,6 +2865,11 @@ func Test_props_with_text_above()
   let buf = RunVimInTerminal('-S XscriptPropsWithTextAbove', #{rows: 9, cols: 60})
   call VerifyScreenDump(buf, 'Test_prop_with_text_above_1', {})
 
+  call term_sendkeys(buf, "ggI")
+  call VerifyScreenDump(buf, 'Test_prop_with_text_above_2', {})
+  call term_sendkeys(buf, "inserted \<Esc>")
+  call VerifyScreenDump(buf, 'Test_prop_with_text_above_3', {})
+
   call StopVimInTerminal(buf)
 endfunc
 

src/version.c

@@ -703,6 +703,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    439,
 /**/
     438,
 /**/