Close #1685 - Move developer documentation to a help file

PULL_REQUEST_TEMPLATE.md

@@ -1,22 +1,8 @@
 <!--
-READ THIS: Before creating a pull request, please consider the following first.
+Before creating a pull request, do the following.
 
-* The most important thing you can do is write tests. Code without tests
-  probably doesn't work, and will almost certainly stop working later on. Pull
-  requests without tests probably won't be accepted, although there are some
-  exceptions.
 * Read the Contributing guide linked above first.
-* If you are adding a new linter, remember to update the README.md file and
-  doc/ale.txt first.
-* If you add or modify a function for converting error lines into loclist items
-  that ALE can work with, please add Vader tests for them. Look at existing
-  tests in the test/handler directory, etc.
-* If you add or modify a function for computing a command line string for
-  running a command, please add Vader tests for that. Look at existing
-  tests in the test/command_callback directory, etc.
-* Generally try and cover anything with Vader tests, although some things just
-  can't be tested with Vader, or at least they can be hard to test. Consider
-  breaking up your code so that some parts can be tested, and generally open up
-  a discussion about it.
-* Have fun!
+* Read the documentation that comes with ALE with `:help ale-development`.
+
+Have fun!
 -->