feat(sql)!: Dont force ansi dialect

[CongLuanTran]

📑 Description

The original configuration for sqlfluff add an extra --dialect ansi argument to the null_ls configuration, forcing the use of ANSI dialect. This is very annoying since it will override the dialect set in the configuration file .sqlfluff and leave little options for the user to use their desired dialect. With this change I remove that extra argument. However, this also means that the user must create a .sqlfluff file in the folder and specify the dialect there. I might adjust the README file to reflect this.

• Remove --dialect ansi extra argument from init.lua
• Adjust the README

Additional Information

[github-actions]

Review Checklist

Does this PR follow the [Contribution Guidelines](development guidelines)? Following is a partial checklist:

Proper conventional commit scoping:

• If you are adding a new plugin, the scope would be the name of the category it is being added into. ex. feat(utility): added noice.nvim plugin

• If you are modifying a pre-existing plugin or pack, the scope would be the name of the plugin folder. ex. fix(noice-nvim): fix LSP handler error

• Pull request title has the appropriate conventional commit type and scope where the scope is the name of the pre-existing directory in the project as described above

• README is properly formatted and uses fenced in links with <url> unless they are inside a [title](url)

• Entry returns a single plugin spec with the new plugin as the only top level spec (not applicable for recipes or packs).

• Proper usage of opts table rather than setting things up with the config function.

• Proper usage of specs table for all specs that are not dependencies of a given plugin (not applicable for recipes or packs).

[Uzaaft]

Waiting on the readme changes.

[CongLuanTran]

README added, but this will a breaking change since it requires a .sqlfluff config file. Without the config file, sqlfluff will not work.