Link: Update link to reference wayback machine

Introduction and other pages was sending students to broken link.

docs/CONTRIBUTING.md

@@ -178,7 +178,7 @@ Pull requests should be focused on a single exercise, issue, or conceptually coh
 
 ### Coding Style
 
-The code in this repository should follow [Pharo with style](https://github.com/SquareBracketAssociates/Booklet-PharoWithStyle) conventions wherever possible. You can also refer to the more generic [Smalltalk with style](http://sdmeta.gforge.inria.fr/FreeBooks/WithStyle/SmalltalkWithStyle.pdf) as well.
+The code in this repository should follow [Pharo with style](https://github.com/SquareBracketAssociates/Booklet-PharoWithStyle) conventions wherever possible. You can also refer to the more generic [Smalltalk with style](https://web.archive.org/web/20200215093658/http://sdmeta.gforge.inria.fr/FreeBooks/WithStyle/SmalltalkWithStyle.pdf) as well.
 
 You should also make use of the built-in code formatter (meta-t FO in the editor) when creating exercises, as well as the code critques.
 

docs/LEARNING.md

@@ -24,7 +24,7 @@ provides a series of full programming courses and videos
 takes you through more advanced topics like graphics and parsing
 * [Pharo with style](https://github.com/SquareBracketAssociates/Booklet-PharoWithStyle):
 is the guide for formatting and designing the Pharo way
-* [Smalltalk with style](http://sdmeta.gforge.inria.fr/FreeBooks/WithStyle/SmalltalkWithStyle.pdf):
+* [Smalltalk with style](https://web.archive.org/web/20200215093658/http://sdmeta.gforge.inria.fr/FreeBooks/WithStyle/SmalltalkWithStyle.pdf):
 is a broader guide for formatting and designing in Smalltalk
 * [Enterprise Pharo - Web Perspective](http://books.pharo.org/enterprise-pharo/):
 covers web applications, http and data

docs/RESOURCES.md

@@ -20,7 +20,7 @@ The following are useful starting points for getting more detailed information a
 ### Docs
 
 * [Pharo with style](https://github.com/SquareBracketAssociates/Booklet-PharoWithStyle)
-* [Smalltalk with style](http://sdmeta.gforge.inria.fr/FreeBooks/WithStyle/SmalltalkWithStyle.pdf)
+* [Smalltalk with style](https://web.archive.org/web/20200215093658/http://sdmeta.gforge.inria.fr/FreeBooks/WithStyle/SmalltalkWithStyle.pdf)
 * [Smalltalk ANSI Standard](http://wiki.squeak.org/squeak/uploads/172/standard_v1_9-indexed.pdf)
 * [Smalltalk Grammar](https://gist.github.com/sin3141592/602700)
 * [Deep Into Pharo](http://books.pharo.org/deep-into-pharo/)