Update findstr.md

[hochun836]

findstr hello there x.y // find hello in there, x.y files
findstr "hello there" x.y // find hello or there in x.y file

[prmerger-automator]

@hochun836 : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[opbld30]

Learn Build status updates of commit 2bf9a03:

✅ Validation status: passed

File	Status	Preview URL	Details
WindowsServerDocs/administration/windows-commands/findstr.md	✅Succeeded

For more details, please refer to the build report.

Note: Broken links written as relative paths are included in the above build report. For broken links written as absolute paths or external URLs, see the broken link report.

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[jborsecnik]

@Xelu86, @robinharwood,

Can you review the proposed changes?

IMPORTANT: When the changes are ready for publication, add a #sign-off comment to signal that the PR is ready for the review team to merge.

#label:"aq-pr-triaged"
@MicrosoftDocs/public-repo-pr-review-team

[Jak-MS]

#assign: @robinharwood, @Xelu86

[prmerger-automator]

@hochun836 : Thanks for your contribution! The author(s) have been notified to review your proposed change.

[prmerger-automator]

@hochun836 : Thanks for your contribution! The author(s) have been notified to review your proposed change.