Don't use the "i" suffix for case-insensitive class descriptions

If the described class is case-sensitive, nothing changes.

If the described class is case-insensitive, its description doesn't
indicate that anymore. The indication was awkward and it was meaningful
only for parser users familiar with PEG.js grammar syntax (typically a
minority). For cases where case insensitivity indication is vital, named
rules can be used to customize the reporting.

Note that literal descriptions already ignore the case-sensitivity flag;
this commit only makes things consistent.

lib/compiler/passes/generate-bytecode.js

@@ -632,7 +632,7 @@ function generateBytecode(ast) {
                 + classDescriptionEscape(part[1])
               : classDescriptionEscape(part);
           }).join("")
-        + "]" + (node.ignoreCase ? "i" : "");
+        + "]";
 
       regexpIndex   = addConst(regexp);
       expectedIndex = addConst([

lib/parser.js

@@ -288,7 +288,7 @@
         peg$c129 = /^[0-9]/,
         peg$c130 = { type: "class", value: "[0-9]", description: "[0-9]" },
         peg$c131 = /^[0-9a-f]/i,
-        peg$c132 = { type: "class", value: "[0-9a-f]i", description: "[0-9a-f]i" },
+        peg$c132 = { type: "class", value: "[0-9a-f]i", description: "[0-9a-f]" },
         peg$c133 = ".",
         peg$c134 = { type: "literal", value: ".", description: "\".\"" },
         peg$c135 = function() { return { type: "any", location: location() }; },

spec/unit/compiler/passes/generate-bytecode.spec.js

@@ -616,7 +616,7 @@ describe("compiler pass |generateBytecode|", function() {
       it("defines correct constants", function() {
         expect(pass).toChangeAST('start = [a]i', constsDetails([
           '/^[a]/i',
-          '{ type: "class", value: "[a]i", description: "[a]i" }'
+          '{ type: "class", value: "[a]i", description: "[a]" }'
         ]));
       });
     });