config(fish): add fish completions for cli tools

dot_config/fish/functions/_nvm_list.fish

@@ -0,0 +1,14 @@
+function _nvm_list
+    set --local versions $nvm_data/*
+
+    set --query versions[1] &&
+        string match --entire --regex -- (
+            string replace --all -- $nvm_data/ "" $versions |
+            string match --regex -- "v\d.+" |
+            string escape --style=regex |
+            string join "|"
+        ) <$nvm_data/.index
+
+    command --all node |
+        string match --quiet --invert --regex -- "^$nvm_data" && echo system
+end