Enable SA1000: Spacing around keywords (#2748)

Author: xtqqczze

eng/CodeAnalysis.src.globalconfig

@@ -1139,8 +1139,7 @@ dotnet_diagnostic.RS2008.severity = warning
 dotnet_diagnostic.SA0001.severity = none
 
 # SA1000: Spacing around keywords
-# suggestion until https://github.com/DotNetAnalyzers/StyleCopAnalyzers/issues/3478 is resolved
-dotnet_diagnostic.SA1000.severity = suggestion
+dotnet_diagnostic.SA1000.severity = warning
 
 # SA1001: Commas should not be preceded by whitespace
 dotnet_diagnostic.SA1001.severity = warning