Capitalize Activate.ps1

[brettcannon]

For #2607

This is to allow Activate.ps1 to work appropriate on Linux for PowerShell Core.

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
• Title summarizes what is changing
• Has a news entry file (remember to thank yourself!)
• Appropriate comments and documentation strings in the code
• Has sufficient logging.
• Has telemetry for enhancements.
• Unit tests & system/integration tests are added/updated
• Test plan is updated as appropriate
• package-lock.json has been regenerated by running npm install (if dependencies have changed)
• The wiki is updated with any design decisions/details.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
0 Code Smells

No Coverage information
1.3% Duplication

[codecov-io]

Codecov Report

Merging #9911 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master    #9911   +/-   ##
=======================================
  Coverage   61.21%   61.21%           
=======================================
  Files         564      564           
  Lines       30061    30061           
  Branches     4545     4545           
=======================================
  Hits        18403    18403           
  Misses      10629    10629           
  Partials     1029     1029

Impacted Files	Coverage Δ
...al/environmentActivationProviders/commandPrompt.ts	92.85% <100%> (ø)	⬆️
src/client/common/utils/platform.ts	76.47% <0%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f551a73...78c1568. Read the comment docs.

[ericsnowcurrently]

LGTM