fix: quick grammar and spelling check (#1402)

packages/web/src/content/docs/docs/index.mdx

@@ -86,7 +86,7 @@ With opencode you can use any LLM provider by configuring their API keys.
 
 We recommend signing up for [Claude Pro](https://www.anthropic.com/news/claude-pro) or [Max](https://www.anthropic.com/max), it's the most cost-effective way to use opencode.
 
-Once you've singed up, run `opencode auth login` and select Anthropic.
+Once you've signed up, run `opencode auth login` and select Anthropic.
 
 ```bash
 $ opencode auth login
@@ -105,7 +105,7 @@ $ opencode auth login
 └
 ```
 
-Alternatively, you can select one of the other providers and adding their API keys.
+Alternatively, you can select one of the other providers and add their API keys.
 
 ---
 
@@ -257,7 +257,7 @@ team](/docs/share).
 /share
 ```
 
-This'll create a link to the current conversation and copy it to your clipboard.
+This will create a link to the current conversation and copy it to your clipboard.
 
 :::note
 Conversations are not shared by default.