fix(purescript-language-server): root dir for Nix files #1954

As seen in the source code:
https://github.com/nwolverson/purescript-language-server/blob/db5584d79e698b02e3df12a1299d5f93262bd5ee/src/LanguageServer/IdePurescript/Main.purs#L391

Nix-related files were added to the Language server to establish the
root. This commit looks to mimic that behavior. The PureScript community
has a lot of Nix-positive users and tooling.

Additionally the docs were updated::
* Reflect the new `root_dir` + `root_pattern` list
* Include a list of ways to install the language server to your project
* Remove the specific, problematic npm install command because
** Globally installing these tools is a bad practice as teams should
   maintain consistent versions in their projects and users are less
   likely to remember to upgrade global packages; new documentation
   suggests to add it to your project, but it doesn’t _not_ say to
   install it globally if desired
** npm is _not_ the only JavaScript package manager
** JavaScript package managers are not the only way to get the language
   server
** Unrelated but technically incorrect: the block was labeled as a shell
   script despite it being a shell session (code block syntax `sh`
   should be `console`)

0 files changed, 0 insertions, 0 deletions