Update issue templates

.github/ISSUE_TEMPLATE/bug_report.md

+---
+name: Bug report
+about: Submit a bug report.
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**DELETE ALL OF THIS TEXT BEFORE SUBMITTING**
+
+If you think you've found a bug, it will be helpful to run with `#define MA_DEBUG_OUTPUT` above your miniaudio implementation like the code below and to include the output with this bug report:
+
+    #define MA_DEBUG_OUTPUT
+    #define MINIAUDIO_IMPLEMENTATION
+    #include "miniaudio.h"
+
+If you are having issues with playback, please run the simple_payback_sine example and report whether or not it's consistent with what's happening in your program.

.github/ISSUE_TEMPLATE/feature_request.md

+---
+name: Feature request
+about: Submit a feature request.
+title: ''
+labels: feature request
+assignees: ''
+
+---
+
+**DELETE ALL OF THIS TEXT BEFORE SUBMITTING**
+
+Thanks for your suggestion! Please make sure the feature doesn't already exist and that it's within the scope of the goals of the project. Otherwise go into as much detail as possible and we'll consider it!

.github/ISSUE_TEMPLATE/general-issue.md

+---
+name: General issue
+about: Submit a general issue.
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**DELETE ALL OF THIS TEXT BEFORE SUBMITTING**
+
+If you have a question about how to use the library, please read the documentation at the top of miniaudio.h and take a look at the examples. Otherwise, feel free to post your issue and we'll get to it as soon as possible!