remove redundent type annotation

pre_commit_hooks/requirements_txt_fixer.py

diff --git a/pre_commit_hooks/requirements_txt_fixer.py b/pre_commit_hooks/requirements_txt_fixer.py
index 1691d80..eff7935 100644
--- a/pre_commit_hooks/requirements_txt_fixer.py
+++ b/pre_commit_hooks/requirements_txt_fixer.py
@@ -40,7 +40,7 @@
 
 def fix_requirements(f):  # type: (IO[bytes]) -> int
     requirements = []  # type: List[Requirement]
-    before = list(f)  # type: List[bytes]
+    before = list(f)
     after = []  # type: List[bytes]
 
     before_string = b''.join(before)