docs: remove outdated pnpm deps

Historically, docs instructed users to install this library as a development dependency. This caused the direct dependency to not be installed (as expected) for pnpm.

Guidance has changed to install the library as a direct dependency instead. As such, the instructions should be updated.

README.md

@@ -18,7 +18,7 @@ The Changelog is [available on GitHub](https://github.com/metonym/svelte-highlig
 npm i svelte-highlight
 
 # pnpm
-pnpm i svelte-highlight highlight.js
+pnpm i svelte-highlight
 
 # Bun
 bun i svelte-highlight
@@ -27,8 +27,6 @@ bun i svelte-highlight
 yarn add svelte-highlight
 ```
 
-Note that [pnpm](https://github.com/pnpm/pnpm) users must also install `highlight.js`.
-
 ## Basic Usage
 
 The `Highlight` component requires two props:

www/components/globals/Index.svelte

@@ -48,7 +48,7 @@
   </Column>
   <Column xlg={6} lg={9}>
     <CodeSnippet code="npm i {PKG_NAME}" /><br />
-    <CodeSnippet code="pnpm i {PKG_NAME} highlight.js" /><br />
+    <CodeSnippet code="pnpm i {PKG_NAME}" /><br />
     <CodeSnippet code="bun add {PKG_NAME}" /><br />
     <CodeSnippet code="yarn add {PKG_NAME}" />
   </Column>