[libcxx] Remove extraneous '---' lines in .clang-format files

NOKEYCHECK=True
GitOrigin-RevId: 462b49f18c6c065e1a0f46ee22cf01b205a24981
diff --git a/.clang-format b/.clang-format
index dc6f2af..b4f56c0 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,6 +1,5 @@
 BasedOnStyle: LLVM
 
----
 Language: Cpp
 
 AlwaysBreakTemplateDeclarations: true
@@ -14,4 +13,3 @@
 
 # libc++ has some long names so we need more than the 80 column limit imposed by LLVM style, for sensible formatting
 ColumnLimit: 120
----