Merge pull request #319 from RhysMacMillan/checklist.md

Additional point under Enhancing Clarity

Author: nsryan2

manual/guides/writing/checklist.md

@@ -43,6 +43,7 @@ As Shakespeare wrote in *Hamlet*, "Brevity is the soul of wit."
 - [ ] Refer to software consistently by name.
 - [ ] Italicize unusual or unfamiliar words or phrases when you use them.
 - [ ] If you use an uncommon word, consider changing it or defining it in its first usage.
+- [ ] Only use the word "significant" when referring to statistical significance.
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