Add --strip-ansi option

doc/long-help.txt

@@ -122,6 +122,10 @@ Options:
       --squeeze-limit <squeeze-limit>
           Set the maximum number of consecutive empty lines to be printed.
 
+      --strip-ansi <when>
+          Specify when to strip ANSI escape sequences from the input. Possible values: always,
+          *never*.
+
       --style <components>
           Configure which elements (line numbers, file headers, grid borders, Git modifications, ..)
           to display in addition to the file contents. The argument is a comma-separated list of