Tweak contribution guide

CONTRIBUTING.md

@@ -1,7 +1,32 @@
+## Reporting Bugs
+
+Please file bugs in the [Github Issue
+Tracker](https://github.com/syncthing/syncthing/issues). Include at
+least the following:
+
+ - What happened
+
+ - What did you expect to happen instead of what *did* happen, if it's
+   not crazy obvious
+
+ - What operating system, operating system version and version of
+   Syncthing you are running
+
+ - The same for other connected nodes, where relevant
+
+ - Screenshot if the issue concerns something visible in the GUI
+
+ - Console log entries, where possible and relevant
+
+If you're not sure whether something is relevant, erring on the side of
+too much information will never get you yelled at. :)
+
+## Contributing Code
+
 Please do contribute! If you want to contribute but are unsure where to
 start, the [Contributions Needed
-topic](http://discourse.syncthing.net/t/contributions-needed/49)
-lists areas in need of attention.
+topic](http://discourse.syncthing.net/t/49) lists areas in need of
+attention. In general, any open issues are fair game!
 
 ## Licensing
 
@@ -16,8 +41,8 @@ to add yourself as a separate commit in your first pull request.
 
 ## Building
 
-[See the
-documentation](http://discourse.syncthing.net/t/building-syncthing/44)
+[See the documentation](http://discourse.syncthing.net/t/44) on how to
+get started with a build environment.
 
 ## Branches
 
@@ -44,7 +69,9 @@ Yes please!
 
 ## Style
 
-`go fmt`
+ - `go fmt`
+
+ - Unix line breaks
 
 ## Documentation
 
@@ -53,4 +80,3 @@ Yes please!
 ## License
 
 MIT
-