Remove dead code. Fix comment typo.

compiler/hsSyn/HsExpr.lhs

@@ -79,8 +79,6 @@ noSyntaxExpr = HsLit (HsString (fsLit "noSyntaxExpr"))
 type CmdSyntaxTable id = [(Name, SyntaxExpr id)]
 -- See Note [CmdSyntaxTable]
 
-noSyntaxTable :: CmdSyntaxTable id
-noSyntaxTable = []
 \end{code}
 
 Note [CmdSyntaxtable]
@@ -88,7 +86,7 @@ Note [CmdSyntaxtable]
 Used only for arrow-syntax stuff (HsCmdTop), the CmdSyntaxTable keeps
 track of the methods needed for a Cmd.
 
-* Before the renamer, this list is 'noSyntaxTable'
+* Before the renamer, this list is an empty list
 
 * After the renamer, it takes the form @[(std_name, HsVar actual_name)]@
   For example, for the 'arr' method

compiler/hsSyn/HsUtils.lhs

@@ -4,7 +4,7 @@
 
 Here we collect a variety of helper functions that construct or
 analyse HsSyn.  All these functions deal with generic HsSyn; functions
-which deal with the intantiated versions are located elsewhere:
+which deal with the instantiated versions are located elsewhere:
 
    Parameterised by	Module
    ----------------     -------------