Skip normalizing case for path during displaying

Because os.getcwd and os.path.abspath both honors original letter-case,
we should not normalize case again when calculating the relative path.

Author: wdhongtw

news/6823.bugfix.rst

@@ -0,0 +1 @@
+This change will preserve path in it's original letter-case during displaying.

src/pip/_internal/utils/misc.py

@@ -190,7 +190,7 @@ def rmtree_errorhandler(
 def display_path(path: str) -> str:
     """Gives the display value for a given path, making it relative to cwd
     if possible."""
-    path = os.path.normcase(os.path.abspath(path))
+    path = os.path.abspath(path)
     if path.startswith(os.getcwd() + os.path.sep):
         path = "." + path[len(os.getcwd()) :]
     return path