mimblewinble -> mimblewimble (#2803)

CONTRIBUTING.md

@@ -6,7 +6,7 @@ The [list of issues](https://github.com/mimblewimble/grin/issues) is a good plac
 
 Additional tests are rewarded with an immense amount of positive karma.
 
-More documentation or updates/fixes to existing documentation are also very welcome. 
+More documentation or updates/fixes to existing documentation are also very welcome.
 
 # PR Guidelines
 
@@ -34,7 +34,7 @@ In case of problems with trying out grin, before starting to contribute, there's
 * And [see the developers chat](https://gitter.im/grin_community/dev) if you have questions about source code files.
   If you explain what you're looking at and what you want to do, we'll try to help you along the way.
 * Also see `docs/*.md` and the folder structure explanations, and [the wiki](https://github.com/mimblewimble/docs/wiki).
-* Further information and discussions are in the [Forum](https://www.grin-forum.org/), the [website](https://grin-tech.org), the [mailing list](https://lists.launchpad.net/mimblewimble/) and news channels like the [@grincouncil](https://twitter.com/grincouncil) and a (mostly unfiltered!) Twitter bot that collects headlines, mailing list posts, and reddit posts related to MimbleWinble/Grin: [@grinmw](https://twitter.com/grinmw)
+* Further information and discussions are in the [Forum](https://www.grin-forum.org/), the [website](https://grin-tech.org), the [mailing list](https://lists.launchpad.net/mimblewimble/) and news channels like the [@grincouncil](https://twitter.com/grincouncil) and a (mostly unfiltered!) Twitter bot that collects headlines, mailing list posts, and reddit posts related to MimbleWimble/Grin: [@grinmw](https://twitter.com/grinmw)
 
 ## Testing