github: Reword issue template

Author: 1st1

.github/ISSUE_TEMPLATE.md

@@ -1,6 +1,8 @@
 <!--
-Thanks for wanting to report an issue you've found in asyncpg. Please fill in
-the template below.
+Thank you for reporting an issue/feature request.
+
+If this is a feature request, please disregard this template.  If this is
+a bug report, please answer to the questions below.
 
 It will be much easier for us to fix the issue if a test case that reproduces
 the problem is provided, with clear instructions on how to run it.
@@ -13,9 +15,9 @@ Thank you!
 * **Python version**:
 * **Platform**:
 * **Do you use pgbouncer?**:
-* **Do you use the wheel package or built locally
-  (if locally, which version of Cython was used)?**:
-* **Can you the issue be reproduced when running under
+* **Did you install asyncpg with pip?**:
+* **If you built asyncpg locally, which version of Cython did you use?**:
+* **Can the issue be reproduced under both asyncio and
   [uvloop](https://github.com/magicstack/uvloop)?**:
 
 <!-- Enter your issue details below this comment. -->