Make some minor stylistic adjustments

Removed a typo and a superfluous comment, changed to property use from backing field in one occasion and adapted the exception message in a switch statement.

Author: MDoerner

Rubberduck.CodeAnalysis/QuickFixes/RemoveEmptyIfBlockQuickFix.cs

@@ -32,7 +32,7 @@ public override void Fix(IInspectionResult result, IRewriteSession rewriteSessio
                     UpdateContext(elseIfBlockContext, rewriter);
                     break;
                 default:
-                    throw new NotSupportedException(nameof(result.Context));
+                    throw new NotSupportedException(result.Context.GetType().ToString());
             }
         }
 

Rubberduck.Parsing/Rewriter/RewriteSessionBase.cs

@@ -47,14 +47,12 @@ public bool TryRewrite()
                 return false;
             }
 
-            lock (_invalidationLockObject)
+            //This is thread-safe because, once invalidated, there is no way back.
+            if (IsInvalidated)
             {
-                if (_isInvalidated)
-                {
-                    Logger.Warn("Tried to execute Rewrite on a RewriteSession that was already invalidated.");
-                    return false;
-                }
-            }
+                Logger.Warn("Tried to execute Rewrite on a RewriteSession that was already invalidated.");
+                return false;
+            }            
 
             if (!_rewritingAllowed(this))
             {

Rubberduck.Refactorings/ExtractInterface/ExtractInterfaceRefactoring.cs

@@ -94,7 +94,7 @@ public void Refactor(Declaration target)
 
         private void AddInterface()
         {
-            //We need to suspend here since addin the interface and rewriting will both trigger a reparse.
+            //We need to suspend here since adding the interface and rewriting will both trigger a reparse.
             var suspendResult = _model.State.OnSuspendParser(this, new[] {ParserState.Ready}, AddInterfaceInternal);
             if (suspendResult != SuspensionResult.Completed)
             {
@@ -122,7 +122,6 @@ private void AddInterfaceInternal()
 
             AddInterfaceMembersToClass(rewriter);
 
-            //We have to reparse here already, because 
             rewriteSession.TryRewrite();
         }