doc: minor rewording to the GitHub issue/pr templates

- Templates are now a bit more consistent with phrasing.
- Simplified a bit.

PR-URL: #7403
Reviewed-By: Claudio Rodriguez <cjrodr@yahoo.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Minwoo Jung <jmwsoft@gmail.com>
Reviewed-By: Michaël Zasso <mic.besace@gmail.com>

.github/ISSUE_TEMPLATE.md

@@ -1,9 +1,9 @@
 <!--
-Thank you for reporting an issue. Please fill in the template below. If unsure
-about something, just do as best as you're able.
+Thank you for reporting an issue.
+Please fill in as much of the template below as you're able.
 
-Version: usually output of `node -v`
-Platform: either `uname -a` output, or if Windows, version and 32 or 64-bit
+Version: output of `node -v`
+Platform: output of `uname -a` (UNIX), or version and 32 or 64-bit (Windows)
 Subsystem: if known, please specify affected core module name
 
 If possible, please provide code that demonstrates the problem, keeping it as

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,23 +1,22 @@
 <!--
 Thank you for your pull request. Please review below requirements.
 
-Bug fixes and new features should include tests and possibly a benchmark.
+Bug fixes and new features should include tests and possibly benchmarks.
 
 Contributors guide: https://github.com/nodejs/node/blob/master/CONTRIBUTING.md
 -->
 
 ##### Checklist
 <!-- Remove items that do not apply. For completed items, change [ ] to [x]. -->
 
-- [ ] `make -j4 test` (UNIX) or `vcbuild test nosign` (Windows) passes
-- [ ] a test and/or benchmark is included
+- [ ] `make -j4 test` (UNIX), or `vcbuild test nosign` (Windows) passes
+- [ ] tests and/or benchmarks are included
 - [ ] documentation is changed or added
-- [ ] the commit message follows commit guidelines
-
+- [ ] commit message follows commit guidelines
 
 ##### Affected core subsystem(s)
-<!-- provide affected core subsystem(s) (like doc, cluster, crypto, etc) -->
+<!-- Provide affected core subsystem(s) (like doc, cluster, crypto, etc). -->
 
 
 ##### Description of change
-<!-- provide a description of the change below this comment -->
+<!-- Provide a description of the change below this comment. -->