fix: fix typo in comment (#3371)

Author: lgbgbl

context.go

@@ -558,7 +558,7 @@ func (c *Context) GetPostFormMap(key string) (map[string]string, bool) {
 	return c.get(c.formCache, key)
 }
 
-// get is an internal method and returns a map which satisfy conditions.
+// get is an internal method and returns a map which satisfies conditions.
 func (c *Context) get(m map[string][]string, key string) (map[string]string, bool) {
 	dicts := make(map[string]string)
 	exist := false