Update os-settings.md for windows set mirror env (#11793)

On Windows devices, the current document requires manual modification of
the current directory.
After modification, it can achieve the same effect as using pwd on Linux
to read the current working directory.

Author: CaiJingLong

src/_includes/docs/community/china/os-settings.md

@@ -12,11 +12,15 @@
    {% capture setpath -%}{{envvarset}}PATH = $pwd.PATH + "/flutter/bin",$env:PATH -join ";"{% endcapture -%}
    {% capture newdir -%}{{prompt}} New-Item -Path '{{installdirsuggestion}}' -ItemType Directory{% endcapture -%}
    {% capture unzip -%} {{prompt}} Expand-Archive .\{% endcapture -%}
-   {% capture permaddexample -%}
-$newPath = "$pwd\flutter\bin;$env:PATH"
+   {% capture permaddexample -%}   
+# cd to flutter dir
+$currentDirectory = Get-Location   
+$newPath = "$currentDirectory\bin;$env:PATH"
 [System.Environment]::SetEnvironmentVariable('Path', $newPath, 'User')
 [System.Environment]::SetEnvironmentVariable('PUB_HOSTED_URL', 'https://pub.flutter-io.cn', 'User')
 [System.Environment]::SetEnvironmentVariable('FLUTTER_STORAGE_BASE_URL', 'https://storage.flutter-io.cn', 'User')
+
+Write-Host ". $PROFILE"
    {% endcapture -%}
 {% else -%}
    {% assign shell = 'your terminal' -%}