Merge pull request #2473 from NoPlagiarism/calc_add_funcs

[Calculator] Allow more functions to be used

Plugins/Flow.Launcher.Plugin.Calculator/Main.cs

@@ -19,6 +19,7 @@ public class Main : IPlugin, IPluginI18n, ISettingProvider
                         @"sin|cos|tan|arcsin|arccos|arctan|" +
                         @"eigval|eigvec|eig|sum|polar|plot|round|sort|real|zeta|" +
                         @"bin2dec|hex2dec|oct2dec|" +
+                        @"factorial|sign|isprime|isinfty|" +
                         @"==|~=|&&|\|\||" +
                         @"[ei]|[0-9]|[\+\-\*\/\^\., ""]|[\(\)\|\!\[\]]" +
                         @")+$", RegexOptions.Compiled);