Issue #26553: Capitalization of HTTP, HTTPS, FTP, and URL

Patch by Anish Shah and Aatish Neupane.
diff --git a/Doc/library/concurrent.futures.rst b/Doc/library/concurrent.futures.rst
index 15858be..ae03f4b 100644
--- a/Doc/library/concurrent.futures.rst
+++ b/Doc/library/concurrent.futures.rst
@@ -153,7 +153,7 @@
            'http://www.bbc.co.uk/',
            'http://some-made-up-domain.com/']
 
-   # Retrieve a single page and report the url and contents
+   # Retrieve a single page and report the URL and contents
    def load_url(url, timeout):
        with urllib.request.urlopen(url, timeout=timeout) as conn:
            return conn.read()