Resolve small nits

Author: Lakshmi Priya Sekar

src/Microsoft.DotNet.CodeFormatting/Rules/HasUnderScoreInPrivateFieldNamesFormattingRule.cs

@@ -24,8 +24,8 @@ namespace Microsoft.DotNet.CodeFormatting.Rules
     internal sealed class HasUnderScoreInPrivateFieldNamesFormattingRule : IFormattingRule
     {
         private static string[] s_keywordsToIgnore = { "public", "internal", "protected", "const" };
-
         private static readonly SyntaxAnnotation s_annotationMarker = new SyntaxAnnotation();
+        private static readonly Regex regex = new Regex("^._");
 
         public async Task<Document> ProcessAsync(Document document, CancellationToken cancellationToken)
         {
@@ -88,7 +88,6 @@ private async Task<Solution> RenameFields(Solution solution, DocumentId document
         private static string GetNewSymbolName(ISymbol symbol)
         {
             var symbolName = symbol.Name.TrimStart('_');
-            Regex regex = new Regex("^._");
             if (regex.IsMatch(symbolName)) symbolName = symbolName.Remove(0, 2);
             if (symbol.IsStatic)
             {