list unsupported features in README.md (#95, #83, #84, #90, #92, #94)

README.md

@@ -73,7 +73,8 @@ docker run -i --rm ghcr.io/itchyny/gojq
 - gojq does not keep the order of object keys. I understand this might cause problems for some scripts but basically, we should not rely on the order of object keys. Due to this limitation, gojq does not have `keys_unsorted` function and `--sort-keys` (`-S`) option. I would implement when ordered map is implemented in the standard library of Go but I'm less motivated. Also, gojq assumes only valid JSON input while jq deals with some JSON extensions; `NaN` and `Infinity`.
 - gojq supports arbitrary-precision integer calculation while jq does not. This is important to keep the precision of numeric IDs or nanosecond values. You can also use gojq to solve some mathematical problems which require big integers. Note that mathematical functions convert integers to floating-point numbers; only addition, subtraction, multiplication, modulo operation, and division (when divisible) keep integer precisions. When you want to calculate floor division of big integers, use `def intdiv($x; $y): ($x - $x % $y) / $y;`, instead of `$x / $y`.
 - gojq fixes some bugs of jq. gojq correctly deletes elements of arrays by `|= empty` ([jq#2051](https://github.com/stedolan/jq/issues/2051)). gojq fixes update assignments including `try` or `//` operator ([jq#1885](https://github.com/stedolan/jq/issues/1885), [jq#2140](https://github.com/stedolan/jq/issues/2140)). gojq consistently counts by characters (not by bytes) in `index`, `rindex`, and `indices` functions; `"１２３４５" | .[index("３"):]` results in `"３４５"` ([jq#1430](https://github.com/stedolan/jq/issues/1430), [jq#1624](https://github.com/stedolan/jq/issues/1624)). gojq can deal with `%f` in `strftime` and `strptime` ([jq#1409](https://github.com/stedolan/jq/issues/1409)).
-- gojq supports reading from YAML input while jq does not. gojq also supports YAML output.
+- gojq does not support some functions intentionally; `get_jq_origin`, `get_prog_origin`, `get_search_list` (unstable, not listed in jq document), `input_line_number`, `$__loc__` (performance issue), `recurse_down` (deprecated in jq). gojq does not support some flags; `--args, --jsonargs, $ARGS.positional` (flag parsing difficulty), `--ascii-output, -a` (performance issue), `--seq` (not used commonly), `--sort-keys, -S` (sorts by default because `map[string]interface{}` does not keep the order), `--unbuffered`. gojq normalizes floating-point numbers to fit to double-precision (64-bit) floating-point numbers. gojq does not support BOM (`encoding/json` does not support this).
+- gojq supports reading from YAML input (`--yaml-input`) while jq does not. gojq also supports YAML output (`--yaml-output`).
 
 ### Color configuration
 The gojq command automatically disables coloring output when the output is not a tty.