Rollup of 7 pull requests

[frewsxcv]

• Successful merges: fixed some clippy warnings in libcollections #40541, Sync all unstable features with Unstable Book; add tidy lint.  #40694, Implement AsRawFd/IntoRawFd for RawFd #40842, Remove unused feature from error index generator #40898, Add example to std::process::abort #40904, Add missing link in unstable-book #40925, Implement all PartialOrd methods for Reverse #40929
• Failed merges:

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @nikomatsakis (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

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[frewsxcv]

@bors r+ p=10

[bors]

📌 Commit 6696e4e has been approved by frewsxcv

[bors]

⌛ Testing commit 6696e4e with merge 65f2900...

[bors]

💔 Test failed - status-appveyor

[frewsxcv]

@bors retry

C:\projects\rust\mingw32\bin\ar.exe: lib\libLLVMMipsAsmPrinter.a: Permission denied
[1279/1629] Linking CXX static library lib\libLLVMMipsDisassembler.a
ninja: build stopped: subcommand failed.
thread 'main' panicked at '
command did not execute successfully, got: exit code: 1

[bors]

⌛ Testing commit 6696e4e with merge f11cec9...

[bors]

💔 Test failed - status-appveyor

[frewsxcv]

[01:54:12]   = note: "gcc" "-Wl,--enable-long-section-names" "-fno-use-linker-plugin" "-Wl,--nxcompat" "-nostdlib" "-Wl,--large-address-aware" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib\\crt2.o" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib\\rsbegin.o" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1-std\\i686-pc-windows-gnu\\release\\deps\\collectionstest-cf7d8872f6b0686a.0.o" "-o" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1-std\\i686-pc-windows-gnu\\release\\deps\\collectionstest-cf7d8872f6b0686a.exe" "-Wl,--gc-sections" "-nodefaultlibs" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1-std\\i686-pc-windows-gnu\\release\\deps" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1-std\\release\\deps" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib" "-Wl,-Bstatic" "-Wl,-Bdynamic" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib" "-l" "test-51dd1e12bb8fc6c0" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib" "-l" "term-9bb4a9959ced7ebc" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib" "-l" "getopts-83c65310844a796d" "-L" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib" "-l" "std-4d6881ec6132b951" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib\\libcompiler_builtins-7ac5a34e9b48514f.rlib" "-l" "kernel32" "-l" "advapi32" "-l" "ws2_32" "-l" "userenv" "-l" "shell32" "-l" "gcc_eh" "-lmingwex" "-lmingw32" "-lgcc" "-lmsvcrt" "-luser32" "-lkernel32" "C:\\projects\\rust\\build\\i686-pc-windows-gnu\\stage1\\lib\\rustlib\\i686-pc-windows-gnu\\lib\\rsend.o"
[01:54:12]   = note: collect2.exe: error: ld returned 5 exit status

I don't even know

@bors retry

[bors]

⌛ Testing commit 6696e4e with merge 7012fd2...

[bors]

💔 Test failed - status-appveyor