Add types to various low-level functions (#31781)

Adds types to various low-level modules. All changes are type-only, no
runtime changes. `tsc` now reports 38 less errors.

One problem was that `@types/sortablejs` does not accept promise return
in its functions which triggered the linter, so I disabled the rules on
those line.

types.d.ts

@@ -3,6 +3,11 @@ declare module '*.svg' {
   export default value;
 }
 
+declare module '*.css' {
+  const value: string;
+  export default value;
+}
+
 declare let __webpack_public_path__: string;
 
 interface Window {
@@ -20,3 +25,7 @@ declare module 'htmx.org/dist/htmx.esm.js' {
   const value = await import('htmx.org');
   export default value;
 }
+
+interface Element {
+  _tippy: import('tippy.js').Instance;
+}