Fix URLs to pull requests in servant-server/CHANGELOG.md

Author: cohei

servant-server/CHANGELOG.md

@@ -5,13 +5,13 @@
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 - Rename `ServantError` to `ClientError`, `ServantErr` to `ServerError`
-  [#1131](https://github.com/haskell-servant/pull/1131)
+  [#1131](https://github.com/haskell-servant/servant/pull/1131)
 - *servant-server* Reorder HTTP failure code priorities
   [#1103](https://github.com/haskell-servant/servant/pull/1103)
 - *servant-server* Re-organise internal modules
   [#1139](https://github.com/haskell-servant/servant/pull/1139)
 - Allow `network-3.0`
-  [#1107](https://github.com/haskell-servant/pull/1107)
+  [#1107](https://github.com/haskell-servant/servant/pull/1107)
 
 0.15
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