docs(examples): fix subject-verb agreement in examples README

"This folders aims" -> "This folder aims". The examples/ directory is a
single folder, so the singular subject agrees with the singular verb.

Signed-off-by: Vidit Patankar <vidit.patankar16@gmail.com>

Author: vidigoat

examples/README.md

@@ -1,5 +1,5 @@
 # Python SDK Examples
 
-This folders aims to provide simple examples of using the Python SDK. Please refer to the
+This folder aims to provide simple examples of using the Python SDK. Please refer to the
 [servers repository](https://github.com/modelcontextprotocol/servers)
 for real-world servers.