feat: change to fish since nu can't properly display prompts...

fish/functions/_tide_remove_unusable_items.fish

@@ -0,0 +1,21 @@
+function _tide_remove_unusable_items
+    # Remove tool-specific items for tools the machine doesn't have installed
+    set -l removed_items
+    for item in aws chruby crystal docker git go java kubectl nix_shell node php rustc terraform toolbox virtual_env
+        set -l cli_names $item
+        switch $item
+            case virtual_env
+                set cli_names python python3
+            case nix_shell
+                set cli_names nix nix-shell
+        end
+        type --query $cli_names || set -a removed_items $item
+    end
+
+    set -U _tide_left_items (for item in $tide_left_prompt_items
+        contains $item $removed_items || echo $item
+    end)
+    set -U _tide_right_items (for item in $tide_right_prompt_items
+        contains $item $removed_items || echo $item
+    end)
+end