patch 8.2.2375: test for RGB color skipped in the terminal

Problem:    Test for RGB color skipped in the terminal.
Solution:   Run the GUI if possible.
diff --git a/src/testdir/test_highlight.vim b/src/testdir/test_highlight.vim
index 8bd03e2..a4c7a72 100644
--- a/src/testdir/test_highlight.vim
+++ b/src/testdir/test_highlight.vim
@@ -781,8 +781,9 @@
 endfunc
 
 " Test for using RGB color values in a highlight group
-func Test_highlight_RGB_color()
-  CheckGui
+func Test_xxlast_highlight_RGB_color()
+  CheckCanRunGui
+  gui -f
   hi MySearch guifg=#110000 guibg=#001100 guisp=#000011
   call assert_equal('#110000', synIDattr(synIDtrans(hlID('MySearch')), 'fg#'))
   call assert_equal('#001100', synIDattr(synIDtrans(hlID('MySearch')), 'bg#'))
diff --git a/src/version.c b/src/version.c
index 98f120b..452fa2d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2375,
+/**/
     2374,
 /**/
     2373,