Update scriptInfo.ts (microsoft#42855)

Author: pushkine

src/server/scriptInfo.ts

@@ -241,7 +241,7 @@ namespace ts.server {
                 this.reloadWithFileText();
             }
 
-            // At this point if svc is present its valid
+            // At this point if svc is present it's valid
             return this.svc;
         }