Fix dead links: Caltech, Sandia, and RTD placeholder

Author: sbryngelson

docs/group-syllabus/computers.md

@@ -72,7 +72,7 @@
                 * daas <- open this one
             * Can complete training and do other things here, like look at your WebCARS to get `WC_ID` (which you need to submit jobs)
         * Onto a computer remotely
-            * https://hpc.sandia.gov/access/ssh/
+            * https://hpc.sandia.gov/
             * Can do the below with DaaS (using my example username, `[usrname]`)
                 * `ssh [usrname]@srngate.sandia.gov`
                 * Passcode: `[PIN] + [yubikey one time pw]`

docs/group-syllabus/improving-your-writing.md

@@ -222,7 +222,7 @@ Over the years, I found the documents below helpful for improving my writing:
 * [Three Sins of Authors in Computer Science and Math](http://www.cs.cmu.edu/~jrs/sins.html)
 * [How to write a great research paper](https://www.microsoft.com/en-us/research/academic-program/write-great-research-paper/)
 * [Notes on writing](http://people.csail.mit.edu/fredo/PUBLI/writing.pdf)
-* [Adam Wierman: Advising](http://users.cms.caltech.edu/~adamw/advising.html)
+* [Adam Wierman: Advising](https://web.archive.org/web/2023/http://users.cms.caltech.edu/~adamw/advising.html)
 * [How to Write a Good Article](http://people.csail.mit.edu/fredo/FredoBadWriting.pdf)
 * [Ten simple Rules for Responsible referencing](https://journals.plos.org/ploscompbiol/article?id=10.1371/journal.pcbi.1006036#sec001)
 * [Writing a science paper some dos and don'ts](https://www.elsevier.com/connect/writing-a-science-paper-some-dos-and-donts)

readme.md

@@ -2,7 +2,7 @@
 
 Documentation for the Computational Physics research group at Georgia Tech.
 
-**[Read the docs here](https://group-docs.readthedocs.io)**
+**[Read the docs here](https://github.com/sbryngelson/group-docs)**
 
 ## License