update elements and fix some bugs

lib/src/prism/components/prism-bison.js

+Prism.languages.bison = Prism.languages.extend('c', {});
+
+Prism.languages.insertBefore('bison', 'comment', {
+        'bison': {
+                // This should match all the beginning of the file
+                // including the prologue(s), the bison declarations and
+                // the grammar rules.
+                pattern: /^[\s\S]*?%%[\s\S]*?%%/,
+                inside: {
+                        'c': {
+                                // Allow for one level of nested braces
+                                pattern: /%\{[\s\S]*?%\}|\{(?:\{[^}]*\}|[^{}])*\}/,
+                                inside: {
+                                        'delimiter': {
+                                                pattern: /^%?\{|%?\}$/,
+                                                alias: 'punctuation'
+                                        },
+                                        'bison-variable': {
+                                                pattern: /[$@](?:<[^\s>]+>)?[\w$]+/,
+                                                alias: 'variable',
+                                                inside: {
+                                                        'punctuation': /<|>/
+                                                }
+                                        },
+                                        rest: Prism.languages.c
+                                }
+                        },
+                        'comment': Prism.languages.c.comment,
+                        'string': Prism.languages.c.string,
+                        'property': /\S+(?=:)/,
+                        'keyword': /%\w+/,
+                        'number': {
+                                pattern: /(^|[^@])\b(?:0x[\da-f]+|\d+)/i,
+                                lookbehind: true
+                        },
+                        'punctuation': /%[%?]|[|:;\[\]<>]/
+                }
+        }
+});