update elements and fix some bugs

lib/src/prism/tests/languages/matlab/keyword_feature.test

+break case catch continue
+else elseif end for
+function if inf NaN
+otherwise parfor pause
+pi return switch
+try while
+
+----------------------------------------------------
+
+[
+        ["keyword", "break"], ["keyword", "case"], ["keyword", "catch"], ["keyword", "continue"],
+        ["keyword", "else"], ["keyword", "elseif"], ["keyword", "end"], ["keyword", "for"],
+        ["keyword", "function"], ["keyword", "if"], ["keyword", "inf"], ["keyword", "NaN"],
+        ["keyword", "otherwise"], ["keyword", "parfor"], ["keyword", "pause"],
+        ["keyword", "pi"], ["keyword", "return"], ["keyword", "switch"],
+        ["keyword", "try"], ["keyword", "while"]
+]
+
+----------------------------------------------------
+
+Checks for all keywords.