feat(base): change diff to have more readable colors

Author: A-Lamia

lua/astrotheme/groups/base.lua

@@ -12,10 +12,10 @@ local function callback(opts)
     CursorColumn = { fg = C.none, bg = C.overlay1 },
     CursorLine = { fg = C.none, bg = C.surface0 },
     Directory = { fg = C.blue, bg = C.none },
-    DiffAdd = { fg = C.overlay2, bg = C.green },
+    DiffAdd = { fg = C.base, bg = C.green },
     DiffChange = { fg = C.yellow, bg = C.none },
-    DiffDelete = { fg = C.overlay3, bg = C.red },
-    DiffText = { fg = C.overlay2, bg = C.yellow },
+    DiffDelete = { fg = C.base, bg = C.red },
+    DiffText = { fg = C.base, bg = C.yellow },
     DiffAdded = { fg = C.green },
     DiffRemoved = { fg = C.red },
     DiffChanged = { fg = C.blue },