Fix a typo in curl.rst (#613)

diff --git a/src/intro/curl.rst b/src/intro/curl.rst
index 195b3ac..ff07d0d 100644
--- a/src/intro/curl.rst
+++ b/src/intro/curl.rst
@@ -62,7 +62,7 @@
 .. note::
     On Microsoft Windows, use double-quotes anywhere you see single-quotes in
     the following examples. Use doubled double-quotes ("") anywhere you see
-    single quotes. For example, if you see:
+    single double-quotes. For example, if you see:
 
     .. code-block:: bash