Make requested changes

Author: TauOmicronMu

message-index/messages/GHC-78892/index.md

@@ -5,7 +5,7 @@ severity: error
 introduced: 9.6.1
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-Pattern matching allows constructors and literals to be used to take apart values, exposing their contents. The `let ... in ...` syntax is used to introduce declarations that are scoped to an expression. See [GHC-04584](https://errors.haskell.org/messages/GHC-78892/) for more information on why expressions aren't permitted in pattern matching. 
+Pattern matching allows constructors and literals to be used to take apart values, exposing their contents. Even though patterns resemble expressions, they are not evaluated. The `let ... in ...` syntax is used to introduce declarations that are scoped to an expression, which doesn't make sense as a pattern without evaluation. See [GHC-04584](https://errors.haskell.org/messages/GHC-78892/) for more information on why expressions aren't permitted in pattern matching. 
 
 ## Example Text 
 ```