[css mode] Add values flex and inline-flex

mode/css/css.js

@@ -525,14 +525,14 @@ CodeMirror.defineMode("css", function(config, parserConfig) {
     "ethiopic-halehame-sid-et", "ethiopic-halehame-so-et",
     "ethiopic-halehame-ti-er", "ethiopic-halehame-ti-et",
     "ethiopic-halehame-tig", "ew-resize", "expanded", "extra-condensed",
-    "extra-expanded", "fantasy", "fast", "fill", "fixed", "flat", "footnotes",
+    "extra-expanded", "fantasy", "fast", "fill", "fixed", "flat", "flex", "footnotes",
     "forwards", "from", "geometricPrecision", "georgian", "graytext", "groove",
     "gujarati", "gurmukhi", "hand", "hangul", "hangul-consonant", "hebrew",
     "help", "hidden", "hide", "higher", "highlight", "highlighttext",
     "hiragana", "hiragana-iroha", "horizontal", "hsl", "hsla", "icon", "ignore",
     "inactiveborder", "inactivecaption", "inactivecaptiontext", "infinite",
     "infobackground", "infotext", "inherit", "initial", "inline", "inline-axis",
-    "inline-block", "inline-table", "inset", "inside", "intrinsic", "invert",
+    "inline-block", "inline-flex", "inline-table", "inset", "inside", "intrinsic", "invert",
     "italic", "justify", "kannada", "katakana", "katakana-iroha", "keep-all", "khmer",
     "landscape", "lao", "large", "larger", "left", "level", "lighter",
     "line-through", "linear", "lines", "list-item", "listbox", "listitem",