Fix typo (#11809)

Yaml -> YAML

Author: changeworld

reference/docs-conceptual/community/2021-updates.md

@@ -259,7 +259,7 @@ New content
 Content updates
 
 - Converted [about_remote_faq](/powershell/scripting/learn/remoting/powershell-remoting-faq) to new
-  Yaml format and moved to conceptual TOC
+  YAML format and moved to conceptual TOC
 - Moved **PSDesiredStateConfiguration** out of 7.2 docs and into PowerShell-Docs-Modules
   - DSC is being removed from PowerShell to become an optional module that is loaded from the
     PowerShell Gallery

reference/docs-conceptual/community/contributing/managing-pull-requests.md

@@ -94,7 +94,7 @@ Can't find service name for `<version>/<modulepath>/About/About.md`
 ```
 
 ```
-Metadata with following name(s) are not allowed to be set in Yaml header, or as file level
+Metadata with following name(s) are not allowed to be set in YAML header, or as file level
 metadata in docfx.json, or as global metadata in docfx.json: `locale`. They are generated by
 Docs platform, so the values set in these 3 places will be ignored. Please remove them from all
 3 places to resolve the warning.