patch 8.2.2797: Search highlight disappears in the Visual area

Problem:    Search highlight disappears in the Visual area.
Solution:   Combine the search attributes. (closes #8134)

src/drawline.c

@@ -1538,6 +1538,9 @@ win_line(
 	    if (area_attr != 0)
 	    {
 		char_attr = hl_combine_attr(line_attr, area_attr);
+		if (!highlight_match)
+		    // let search highlight show in Visual area if possible
+		    char_attr = hl_combine_attr(search_attr, char_attr);
 # ifdef FEAT_SYN_HL
 		char_attr = hl_combine_attr(syntax_attr, char_attr);
 # endif

src/testdir/dumps/Test_hlsearch_visual_1.dump

@@ -0,0 +1,6 @@
+|x+0&#ffffff0@2| |y+2&#ffff4012|y+2&#e0e0e08@1| +0&&|z@2| | +0&#ffffff0@27
+|x+0&#e0e0e08@2| |y+2&&@2| +0&&|z@2| | +0&#ffffff0@27
+|x+0&#e0e0e08@2| |y+2&&>y+2&#ffff4012@1| +0&#ffffff0|z@2| @28
+|~+0#4040ff13&| @38
+|~| @38
+|-+2#0000000&@1| |V|I|S|U|A|L| |-@1|3+0&&| @8|3|,|6| @10|A|l@1| 

src/testdir/test_search.vim

@@ -964,6 +964,26 @@ func Test_hlsearch_dump()
   call delete('Xhlsearch_script')
 endfunc
 
+func Test_hlsearch_and_visual()
+  CheckOption hlsearch
+  CheckScreendump
+
+  call writefile([
+	\ 'set hlsearch',
+        \ 'call setline(1, repeat(["xxx yyy zzz"], 3))',
+        \ 'hi Search cterm=bold',
+	\ '/yyy',
+	\ 'call cursor(1, 6)',
+	\ ], 'Xhlvisual_script')
+  let buf = RunVimInTerminal('-S Xhlvisual_script', {'rows': 6, 'cols': 40})
+  call term_sendkeys(buf, "vjj")
+  call VerifyScreenDump(buf, 'Test_hlsearch_visual_1', {})
+  call term_sendkeys(buf, "\<Esc>")
+
+  call StopVimInTerminal(buf)
+  call delete('Xhlvisual_script')
+endfunc
+
 func Test_incsearch_substitute()
   CheckOption incsearch
 

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2797,
 /**/
     2796,
 /**/