Replace deprecated json.schemastore.org with www.schemastore.org (#42336)

Release Notes:

- N/A

According to
[microsoft/vscode#254689](https://github.com/microsoft/vscode/issues/254689),
the json.schemastore.org domain has been deprecated and should now use
www.schemastore.org (or schemastore.org) instead.

This PR updates all occurrences of the old domain within the Zed
codebase,
including code, documentation, and configuration files.

.github/ISSUE_TEMPLATE/config.yml

@@ -1,4 +1,4 @@
-# yaml-language-server: $schema=https://json.schemastore.org/github-issue-config.json
+# yaml-language-server: $schema=https://www.schemastore.org/github-issue-config.json
 blank_issues_enabled: false
 contact_links:
   - name: Feature Request