doc: trim GitHub template comments

Make the comments in the GitHub templates slightly more concise.

PR-URL: #6755
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>

.github/ISSUE_TEMPLATE.md

@@ -1,19 +1,16 @@
 <!--
-Thanks for wanting to report an issue you've found in Node.js. Please fill in
-the template below by replacing the html comments with an appropriate answer.
-If unsure about something, just do as best as you're able.
+Thank you for reporting an issue. Please fill in the template below. If unsure
+about something, just do as best as you're able.
 
-version: usually output of `node -v`
-platform:  either `uname -a` output, or if Windows, version and 32 or 64-bit.
-subsystem:  optional -- if known please specify affected core module name.
+Version: usually output of `node -v`
+Platform: either `uname -a` output, or if Windows, version and 32 or 64-bit
+Subsystem: if known, please specify affected core module name
 
 It will be much easier for us to fix the issue if a test case that reproduces
 the problem is provided. Ideally this test case should not have any external
 dependencies. We understand that it is not always possible to reduce your code
 to a small test case, but we would appreciate to have as
 much data as possible.
-
-Thank you!
 -->
 
 * **Version**:

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,20 +1,18 @@
 <!--
-Thank you for submitting a pull request to Node.js. Before you submit, please
-review below requirements and walk through the checklist. You can 'tick'
-a box by using the letter "x": [x].
+Thank you for your pull request. Please review below requirements and walk
+through the checklist. You can 'tick' a box by using the letter "x": [x].
 
-Run the test suite by invoking: `make -j4 lint test` on linux or
-`vcbuild test nosign` on Windows.
+Run the test suite with: `make -j4 test` on UNIX or `vcbuild test nosign` on
+Windows.
 
 If this aims to fix a regression or you’re adding a feature, make sure you also
-write a test. Finally – if possible – a benchmark that quantifies your changes.
+write a test. If possible, include a benchmark that quantifies your changes.
 
 Finally, read through our contributors guide and make adjustments as necessary:
 https://github.com/nodejs/node/blob/master/CONTRIBUTING.md
 -->
 
 ##### Checklist
-
 <!-- remove lines that do not apply to you -->
 
 - [ ] tests and code linting passes
@@ -24,10 +22,8 @@ https://github.com/nodejs/node/blob/master/CONTRIBUTING.md
 
 
 ##### Affected core subsystem(s)
-
 <!-- provide affected core subsystem(s) (like doc, cluster, crypto, etc) -->
 
 
 ##### Description of change
-
 <!-- provide a description of the change below this comment -->