Adds Powershell one-liner to run clang-format (#684)

CONTRIBUTING.md

@@ -14,6 +14,15 @@ Our CI system will automatically check your PR to ensure that it fits [formattin
 #### tidy-format-validation
 If the tidy-format-validation check fails, then you need to run clang-format. Below is a command that can be used on Linux. Most modern IDEs have a clang-format plugin that can be used. The [.clang-format file can be found here](https://github.com/Kenix3/libultraship/blob/main/.clang-format)
 ##### Running clang-format
+###### From within the LUS directory.
+Ensure clang-format-12 is installed and available through your system path.
+
+Bash:
 ```
 find src include -name "*.cpp" -o -name "*.h" | sed 's| |\\ |g' | xargs clang-format-12 -i
 ```
+
+Powershell:
+```
+Get-ChildItem -Recurse -Path .\src -Include *.cpp, *.h -File | ForEach-Object { clang-format-12.exe -i $_.FullName }
+```