fix(hl): add missing diff highlight groups

Author: A-Lamia

lua/astrotheme/groups/base.lua

@@ -14,6 +14,14 @@ local function callback()
     DiffChange = { fg = C.yellow, bg = C.none },
     DiffDelete = { fg = C.overlay3, bg = C.red },
     DiffText = { fg = C.overlay2, bg = C.yellow },
+    DiffAdded = { fg = C.green },
+    DiffRemoved = { fg = C.red },
+    DiffChanged = { fg = C.blue },
+    DiffOldFile = { fg = C.orange },
+    DiffNewFile = { fg = C.green },
+    DiffFile = { fg = C.blue },
+    DiffLine = { fg = C.overlay0 },
+    DiffIndexLine = { fg = C.cyan },
     ErrorMsg = { fg = C.red, bg = C.none },
     WinSeparator = { fg = C.overlay1, bg = C.none },
     Folded = { fg = C.subtext0, bg = C.none },