Merge pull request sagemath#51 from sagemath/kcrisman-patch-3

Fix SMC references

Author: dimpase

sagetex.dtx

@@ -1054,19 +1054,19 @@ suggestions.
 %
 % \subsubsection{The 21st century way}
 %
-% The SageMathCloud
-% (\href{http://cloud.sagemath.com}{\texttt{cloud.sagemath.com}}) service has
+% CoCalc
+% (\href{https://cocalc.com/}{\texttt{cocalc.com/}}) has
 % full support for \ST, is free to use, and has many fantastic
 % collaboration features. If you somehow want to collaborate on a
-% \ST-enabled \TeX document with a colleague, using SageMathCloud is one
+% \ST-enabled \TeX document with a colleague, using CoCalc is one
 % of the best and easiest ways to do it. You and your collaborators
 % simply create an account, then make a project for your collaboration,
 % and add all the collaborators to the project. Then you can all enjoy
 % realtime collaborative editing, PDF previews, chat, and more.
 %
 % \subsubsection{The $N$th century way, for $N < 21$}
 %
-% Using anything other than SageMathCloud, |git|, or similar tools these
+% Using anything other than CoCalc, |git|, or similar tools these
 % days seems pretty primitive. If emailing |.tex| files back and forth
 % seems perfectly reasonable to you, or if you have to send a file to a
 % journal, the easiest way is to simply include with your document the