Fix broken markdown in csky-unknown-linux-gnuabiv2.md

Author: mbrubeck

src/doc/rustc/src/platform-support/csky-unknown-linux-gnuabiv2.md

@@ -50,6 +50,7 @@ cc = "${TOOLCHAIN_PATH}/bin/csky-linux-gnuabiv2-gcc"
 [target.csky-unknown-linux-gnuabiv2hf]
 # ADJUST THIS PATH TO POINT AT YOUR TOOLCHAIN
 cc = "${TOOLCHAIN_PATH}/bin/csky-linux-gnuabiv2-gcc"
+```
 
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