Fix fuchsia target triple to unbreak docs.rs build (#2634)

Author: dtolnay

Cargo.toml

@@ -22,7 +22,7 @@ targets = [
   "x86_64-unknown-openbsd",
   "x86_64-unknown-netbsd",
   "x86_64-unknown-dragonfly",
-  "x86_64-fuchsia",
+  "x86_64-unknown-fuchsia",
   "x86_64-unknown-redox",
   "x86_64-unknown-illumos"
 ]

README.md

@@ -97,7 +97,7 @@ The following targets are supported by `nix`:
    <td>
     <li>armv7-unknown-linux-uclibceabihf</li>
     <li>powerpc64-unknown-linux-gnu</li>
-    <li>x86_64-fuchsia</li>
+    <li>x86_64-unknown-fuchsia</li>
     <li>x86_64-unknown-dragonfly</li>
     <li>x86_64-unknown-haiku</li>
     <li>x86_64-unknown-linux-gnux32</li>