Continued Nushell Updates and Documentation Improvements

- jt [bumped reedline](https://github.com/nushell/nushell/pull/4806), and [ensurde exit codes in more cases](https://github.com/nushell/nushell/pull/4804), and [Ensured exit codes in more cases](https://github.com/nushell/nushell/pull/4803), and [Moved completions to DeclId](https://github.com/nushell/nushell/pull/4801), and [Fixed the panic when using externs + subexpression](https://github.com/nushell/nushell/pull/4799), and [Allowed passing block literals to do](https://github.com/nushell/nushell/pull/4798), and added [Simplify `empty?`, improve `default`](https://github.com/nushell/nushell/pull/4797), and [Fixed expansion of row condition implied it](https://github.com/nushell/nushell/pull/4795), and [Added the proper workarounds for short flags](https://github.com/nushell/nushell/pull/4794), and [Allowed quotes in a `register` call](https://github.com/nushell/nushell/pull/4793), and [Changed `select` to match 0.44](https://github.com/nushell/nushell/pull/4792), and [Made `reduce -n` more sensible](https://github.com/nushell/nushell/pull/4791), and [Made date values more readable](https://github.com/nushell/nushell/pull/4790), and [Removed duplicate code](https://github.com/nushell/nushell/pull/4789), and [Added support for var decl spans](https://github.com/nushell/nushell/pull/4787), and [Reverted "Make `if` blocks work like a def-env"](https://github.com/nushell/nushell/pull/4782), and [Fixed external extra](https://github.com/nushell/nushell/pull/4777), and [Added support for default values to params and flags](https://github.com/nushell/nushell/pull/4770), and [Fixed rest parsing](https://github.com/nushell/nushell/pull/4765), and added [More nuon tests, fix table print](https://github.com/nushell/nushell/pull/4762), and [Simplify group/window into their own commands](https://github.com/nushell/nushell/pull/4760), and [Bump reedline](https://github.com/nushell/nushell/pull/4747), and [Added more multiline pipeline forms](https://github.com/nushell/nushell/pull/4740), and [Made `if` blocks work like a def-env](https://github.com/nushell/nushell/pull/4656) - wingertge [Removed unused `ntdef.h` include](https://github.com/nushell/nushell/pull/4767), and [Added serialization for JSON and form bodies in `post`](https://github.com/nushell/nushell/pull/4764), and [Added basic resource file for Windows binary](https://github.com/nushell/nushell/pull/4745), and [Added back `--append` flag to `save` command](https://github.com/nushell/nushell/pull/4744), and [Allowed save to accept a list of strings](https://github.com/nushell/nushell/pull/4743) - stormasm [Updated the Readme for the dataframe directory](https://github.com/nushell/nushell/pull/4757) ## Documentation - sebastian-xyz [Switched search provider](https://github.com/nushell/nushell.github.io/pull/277), and [added more german documentation](https://github.com/nushell/nushell.github.io/pull/259) - rgwood [Added RSS feed for blog](https://github.com/nushell/nushell.github.io/pull/276), and [Updated lists page for latest Nu](https://github.com/nushell/nushell.github.io/pull/275), and added [Node+VuePress TLC](https://github.com/nushell/nushell.github.io/pull/268), and [Updated working_with_lists for latest Nu](https://github.com/nushell/nushell.github.io/pull/267), and [Added remaining missing block parameters](https://github.com/nushell/nushell.github.io/pull/265), and [Updated intro for latest Nu version](https://github.com/nushell/nushell.github.io/pull/264), and [Updated Windows build-from-source requirements](https://github.com/nushell/nushell.github.io/pull/258), and [Removed math mode mentions, moved short hand syntax documentation](https://github.com/nushell/nushell.github.io/pull/257), and added [Nu book: grammar + spelling pass](https://github.com/nushell/nushell.github.io/pull/256), and [Added case sensitivity section to operators page](https://github.com/nushell/nushell.github.io/pull/255), and [Updated command input/output docs](https://github.com/nushell/nushell.github.io/pull/254)

This segment details more updates to Nushell, including improvements to exit codes, completion handling, and command functionalities like 'empty?', 'default', 'select', and 'reduce'. It also covers fixes for parsing and external command execution. Wingertge contributed updates related to 'post' command serialization, the 'save' command and Windows resource file. The documentation saw improvements from sebastian-xyz and rgwood, including search provider updates, german translation, RSS feed addition, and updates to reflect the latest Nushell version and syntax.