[improve][doc] Clarify maven running environments under windows

[nullscript]

Motivation

I tried to build my Pulsar environment by following README.md, but failed. Because I used Powershell to run maven command line on Windows, maven recognized windows and used rename-netty-native-libs.cmd , powershell can't run cmd. Even I annotate the windows profile, let maven run rename-netty-native-libs.sh on powershell, but there is lacking many Linux commands on Powershell, such as mktemp.
So I think it is better to clarify the command line running environment in windows to reduce misunderstandings.

Modifications

Clarify the maven running environments under windows.
Other minor fixes, e.g. first word capitalization this -> This

• doc
• doc-required
• doc-not-needed
• doc-complete

[github-actions]

@nullscript Please add the following content to your PR description and select a checkbox:

- [ ] `doc` <!-- Your PR contains doc changes -->
- [ ] `doc-required` <!-- Your PR changes impact docs and you will update later -->
- [ ] `doc-not-needed` <!-- Your PR changes do not impact docs -->
- [ ] `doc-complete` <!-- Docs have been already added -->

[Anonymitaet]

@coderzc could you please review this PR from a technical perspective? Thank you!

[tisonkun]

Thanks for your contribution @nullscript!

LGTM. Pending for merging...

[nullscript]

Thanks for reviewing and updating!