tidied up single-quote character in WACC Language spec

WACCLangSpec.tex

@@ -168,14 +168,14 @@ extended with some basic regular expression notation that simplifies the present
   
   <bool-liter> ::= `true' | `false'
   
-  <char-liter> ::= `\'' <character> `\''  
+  <char-liter> ::= `\textquotesingle' <character> `\textquotesingle'  
 
   <str-liter> ::= `\"' <character>* `\"'  
   
-  <character> ::= "any-ASCII-character-except-`\\'-`\''-`\"'" 
+  <character> ::= "any-ASCII-character-except-`\\'-`\textquotesingle'-`\"'" 
     \alt `\\' <escaped-char>   
 
-  <escaped-char> ::= `0' | `b' | `t' | `n' | `f' | `r' | `\"' | `\'' | `\\'
+  <escaped-char> ::= `0' | `b' | `t' | `n' | `f' | `r' | `\"' | `\textquotesingle' | `\\'
 
   <array-liter> ::= `[' ( <expr> (`,' <expr>)* )? `]'