Remove -i option (#704)

In-place editing should be implemented with builtins for file I/O.

docs/content/3.manual/manual.yml

@@ -174,10 +174,6 @@ sections:
 
         Like `-r` but jq won't print a newline after each output.
 
-      * `--in-place` / `-i`:
-
-        Edit the (first) file in-place.
-
       * `-f filename` / `--from-file filename`:
 
         Read filter from the file rather than from a command line, like