eparse.y: drop overspecified associativity for assignment

Parser infelicity is detected by bison --warnings as:

    ./eparse.y:51.1-6: warning: useless precedence and associativity for '=' [-Wprecedence]
       51 | %right  <str> '='
          | ^~~~~~
    ./eparse.y:62.1-5: warning: useless associativity for UNARY, use %precedence [-Wprecedence]
       62 | %left   <str> UNARY
          | ^~~~~
    ./eparse.y:51.1-6: warning: useless precedence and associativity for '=' [-Wprecedence]
       51 | %right  <str> '='
          | ^~~~~~
    ./eparse.y:62.1-5: warning: useless associativity for UNARY, use %precedence [-Wprecedence]
       62 | %left   <str> UNARY
          | ^~~~~

Benerated parser did not change the output.

src/eparse.y

@@ -48,7 +48,7 @@ static void yyerror(char *);
 	}
 
 %left   <str> ','
-%right  <str> '='
+%token  <str> '='
 %left   <str> LOR
 %left   <str> LAND
 %left   <str> '|'
@@ -59,7 +59,7 @@ static void yyerror(char *);
 %left   <str> SHL  SHR
 %left   <str> '+'  '-'
 %left   <str> '*'  '/'  '%'
-%left   <str> UNARY
+%precedence  <str> UNARY
 
 %token  <val> ISYM
 %token  <val> SYM