Add missing punctuation.

To keep formatting consistent, each step title should end with a colon and all sentences should have ending punctuation.
Merge pull request #457 from edull24/patch-1

Add missing punctuation.
Remove duplicated test
Merge pull request #463 from hojs/duplicated-test

Remove duplicated test
adding command line task completion for powershell
Merge pull request #467 from staxmanade/master

Adding command line task completion for PowerShell
PowerShell completion caching strategy

Adding a basic strategy which improves the performance of powershell completion.
Merge pull request #469 from staxmanade/master

PowerShell completion caching strategy
fixed typo in testing.md
Merge pull request #471 from mcharytoniuk/patch-1

typo in testing.md
Update powershell completion instructions.
correct regression
Merge pull request #473 from staxmanade/patch-1

Update powershell completion instructions.
Update github raw url
Merge pull request #485 from watilde/update-github-raw-url

Update github raw url
Replace event-stream with merge-stream

Closes #462
Followup to b520a4930a6292e4521cd25b13c57658c90911f8
add --tasks-simple flag and update autocompletion scripts to use that, closes #474
3.7 changelog
liftoff 0.11 compatability