Move bug report text from website into contributing file

.github/CONTRIBUTING.md

@@ -4,14 +4,26 @@ Contributing to seaborn
 General support
 ---------------
 
-General support questions ("how do I do <x>?") are most at home on [StackOverflow](https://stackoverflow.com/), where they will be seen by more people and are more easily searchable. StackOverflow has a `[seaborn]` tag, which will bring the question to the attention of people who might be able to answer.
+General support questions ("how do I do X?") are most at home on either [StackOverflow](https://stackoverflow.com/) or [discourse](https://discourse.matplotlib.org/c/3rdparty/seaborn/21), which have a larger audience of people who will see your post and may be able to offer assistance. StackOverflow is better for specific issues, while discourse is better for more open-ended discussion. Your chance of getting a quick answer will be higher if you include runnable code, a precise statement of what you are hoping to achieve, and a clear explanation of the problems that you have encountered.
 
 Reporting bugs
 --------------
 
-If you have encountered a bug in seaborn, please report it on the [Github issue tracker](https://github.com/mwaskom/seaborn/issues/new). It is only really possible to address bug reports if they include a reproducible script using randomly-generated data or one of the example datasets (accessed through `seaborn.load_dataset()`). Please also specify your versions of seaborn and matplotlib, as well as which matplotlib backend you are using.
+If you think you've encountered a bug in seaborn, please report it on the [Github issue tracker](https://github.com/mwaskom/seaborn/issues/new). To be useful, bug reports must include the following information:
+
+- A reproducible code example that demonstrates the problem
+- The output that you are seeing (an image of a plot, or the error message)
+- A clear explanation of why you think something is wrong
+- The specific versions of seaborn and matplotlib that you are working with
+
+Bug reports are easiest to address if they can be demonstrated using one of the example datasets from the seaborn docs (i.e. with `seaborn.load_dataset`). Otherwise, it is preferable that your example generate synthetic data to reproduce the problem. If you can only demonstrate the issue with your actual dataset, you will need to share it, ideally as a csv. Note that you can upload a csv directly to a github issue thread, but it must have a `.txt` suffix.
+
+If you've encountered an error, searching the specific text of the message before opening a new issue can often help you solve the problem quickly and avoid making a duplicate report.
+
+Because matplotlib handles the actual rendering, errors or incorrect outputs may be due to a problem in matplotlib rather than one in seaborn. It can save time if you try to reproduce the issue in an example that uses only matplotlib, so that you can report it in the right place. But it is alright to skip this step if it's not obvious how to do it.
+
 
 New features
 ------------
 
-If you think there is a new feature that should be added to seaborn, you can open an issue to discuss it. However, seaborn's development has become increasingly conservative, and the answer to most feature requests or proposed additions is "no". Polite requests with an explanation of the proposed feature's virtues will usually get an explanation; feature requests that say "I would like feature X, you need to add it" typically won't.
+If you think there is a new feature that should be added to seaborn, you can open an issue to discuss it. But please be aware that current development efforts are mostly focused on standardizing the API and internals, and there may be relatively low enthusiasm for novel features that do not fit well into short- and medium-term develpoment plans.