feat: styling updates (#10)

Updated some plugins to use custom git and diagnostic symbols, also
changed the line number color to match my system highlight color
(catppuccin peach).

config/plugins/editor/neo-tree.nix

@@ -18,6 +18,20 @@
         expanderExpanded = " ";
         expanderHighlight = "NeoTreeExpander";
       };
+
+      gitStatus = {
+        symbols = {
+          added = " ";
+          conflict = "󰩌 ";
+          deleted = "󱂥";
+          ignored = " ";
+          modified = " ";
+          renamed = "󰑕";
+          staged = "󰩍";
+          unstaged = "";
+          untracked = "";
+        };
+      };
     };
   };