Fix precedence of negation vs comparison

Author: mntnorv

jmespath-core/src/main/antlr4/io/burt/jmespath/parser/JmesPath.g4

@@ -6,8 +6,8 @@ expression
   : expression '.' chainedExpression # chainExpression
   | expression bracketSpecifier # bracketedExpression
   | bracketSpecifier # bracketExpression
-  | expression COMPARATOR expression # comparisonExpression
   | '!' expression # notExpression
+  | expression COMPARATOR expression # comparisonExpression
   | expression '&&' expression # andExpression
   | expression '||' expression # orExpression
   | identifier # identifierExpression

jmespath-core/src/main/java/io/burt/jmespath/node/NegateNode.java

@@ -22,6 +22,11 @@ protected boolean internalEquals(Object o) {
     return negated.equals(other.negated);
   }
 
+  @Override
+  protected String internalToString() {
+    return negated.toString();
+  }
+
   @Override
   protected int internalHashCode() {
     return 17 + 31 * negated.hashCode();

jmespath-core/src/test/java/io/burt/jmespath/parser/ParserTest.java

@@ -843,6 +843,17 @@ public void negatedSelectionExpression() {
     assertThat(actual, is(expected));
   }
 
+  @Test
+  public void negatedComparison() {
+    Expression<Object> expected = Comparison(
+      "==",
+      Negate(Property("foo")),
+      JsonLiteral("false")
+    );
+    Expression<Object> actual = compile("!foo == `false`");
+    assertThat(actual, is(expected));
+  }
+
   @Test
   public void bareJsonLiteralExpression() {
     Expression<Object> expected = JsonLiteral("{}");