chore: fix typos in code comments (#18860)

Fixes four typos in code comments (no behavioral change):

- `packages/svelte/src/index-client.js`: `noone` -> `no one`
- `packages/svelte/src/internal/client/dom/css.js`: `Therfore` ->
`Therefore`
- `packages/svelte/src/internal/client/runtime.js`: `loosing` ->
`losing`
- `packages/svelte/src/internal/server/index.js`: `aswell` -> `as well`

Checklist: title prefixed with `chore:`; comment-only change so no
changeset and no behavior affected.

Co-authored-by: Dextheking1 <Dextheking1@users.noreply.github.com>

packages/svelte/src/internal/client/dom/css.js

@@ -12,7 +12,7 @@ export function append_styles(anchor, css) {
 	// Use an effect to ensure `anchor` is in the DOM, otherwise getRootNode() will yield wrong results
 	effect(() => {
 		// Bit of a hack: branches.js/each.js use offscreen fragments with temporary text nodes that will
-		// never be connected to the real dom. Therfore walk up to the branch that has created the component
+		// never be connected to the real dom. Therefore walk up to the branch that has created the component
 		// whose styles we want to append, and check its node instead. It will be connected by the time we get here.
 		anchor = active_effect?.parent?.nodes?.start ?? anchor;
 		var root = anchor.getRootNode();

packages/svelte/src/internal/client/runtime.js

@@ -410,7 +410,7 @@ function remove_reaction(signal, dependency) {
 		// In a fork it's possible that a derived is executed and gets reactions, then commits, but is
 		// never re-executed. This is possible when the derived is only executed once in the context
 		// of a new branch which happens before fork.commit() runs. In this case, the derived still has
-		// UNINITIALIZED as its value, and then when it's loosing its reactions we need to ensure it stays
+		// UNINITIALIZED as its value, and then when it's losing its reactions we need to ensure it stays
 		// DIRTY so it is reexecuted once someone wants its value again.
 		if (derived.v !== UNINITIALIZED) {
 			update_derived_status(derived);