FIX TYPO: Gin by default useR -> ... useS (#3324)

routergroup.go

@@ -161,7 +161,7 @@ func (group *RouterGroup) StaticFile(relativePath, filepath string) IRoutes {
 
 // StaticFileFS works just like `StaticFile` but a custom `http.FileSystem` can be used instead..
 // router.StaticFileFS("favicon.ico", "./resources/favicon.ico", Dir{".", false})
-// Gin by default user: gin.Dir()
+// Gin by default uses: gin.Dir()
 func (group *RouterGroup) StaticFileFS(relativePath, filepath string, fs http.FileSystem) IRoutes {
 	return group.staticFileHandler(relativePath, func(c *Context) {
 		c.FileFromFS(filepath, fs)
@@ -189,7 +189,7 @@ func (group *RouterGroup) Static(relativePath, root string) IRoutes {
 }
 
 // StaticFS works just like `Static()` but a custom `http.FileSystem` can be used instead.
-// Gin by default user: gin.Dir()
+// Gin by default uses: gin.Dir()
 func (group *RouterGroup) StaticFS(relativePath string, fs http.FileSystem) IRoutes {
 	if strings.Contains(relativePath, ":") || strings.Contains(relativePath, "*") {
 		panic("URL parameters can not be used when serving a static folder")