Resolve merge conflict

diff --cc src/doc/unstable-book/src/SUMMARY.md
index fa8be7bb23fb95b49d198bcc7b9278d6c01f47c4,ee4e568a5ca9af263cd3fc50537d3cd18b652a1b..1cfb46530237c1361a4893f832fd732d37b3c8d6
--- 1/src/doc/unstable-book/src/SUMMARY.md
--- 2/src/doc/unstable-book/src/SUMMARY.md
+++ b/src/doc/unstable-book/src/SUMMARY.md
@@@ -71,6 -71,8 +71,7 @@@
      - [prelude_import](language-features/prelude-import.md)
      - [proc_macro](language-features/proc-macro.md)
      - [quote](language-features/quote.md)
 -    - [relaxed_adts](language-features/relaxed-adts.md)
+     - [repr_align](language-features/repr-align.md)
      - [repr_simd](language-features/repr-simd.md)
      - [rustc_attrs](language-features/rustc-attrs.md)
      - [rustc_diagnostic_macros](language-features/rustc-diagnostic-macros.md)
@@@ -224,4 -226,4 +225,3 @@@
      - [windows_net](library-features/windows-net.md)
      - [windows_stdio](library-features/windows-stdio.md)
      - [zero_one](library-features/zero-one.md)
-->>>>>> Add top level sections to the Unstable Book.

diff --cc src/libsyntax/feature_gate.rs
Simple merge