feat: add usort (#167)

* feat: add usort

* formatting via stdin

README.md

@@ -263,6 +263,7 @@ You can view this list in vim with `:help conform-formatters`
 - [trim_newlines](https://www.gnu.org/software/gawk/manual/gawk.html) - Trim new lines with awk.
 - [trim_whitespace](https://www.gnu.org/software/gawk/manual/gawk.html) - Trim whitespaces with awk.
 - [uncrustify](https://github.com/uncrustify/uncrustify) - A source code beautifier for C, C++, C#, ObjectiveC, D, Java, Pawn and Vala.
+- [usort](https://github.com/facebook/usort) - Safe, minimal import sorting for Python projects.
 - [xmlformat](https://github.com/pamoller/xmlformatter) - xmlformatter is an Open Source Python package, which provides formatting of XML documents.
 - [yamlfix](https://github.com/lyz-code/yamlfix) - A configurable YAML formatter that keeps comments.
 - [yamlfmt](https://github.com/google/yamlfmt) - yamlfmt is an extensible command line tool or library to format yaml files.

doc/conform.txt

@@ -284,6 +284,7 @@ FORMATTERS                                                    *conform-formatter
 `trim_whitespace` - Trim whitespaces with awk.
 `uncrustify` - A source code beautifier for C, C++, C#, ObjectiveC, D, Java,
              Pawn and Vala.
+`usort` - Safe, minimal import sorting for Python projects.
 `xmlformat` - xmlformatter is an Open Source Python package, which provides
             formatting of XML documents.
 `yamlfix` - A configurable YAML formatter that keeps comments.

lua/conform/formatters/usort.lua

@@ -0,0 +1,15 @@
+local util = require("conform.util")
+
+---@type conform.FileFormatterConfig
+return {
+  meta = {
+    url = "https://github.com/facebook/usort",
+    description = "Safe, minimal import sorting for Python projects.",
+  },
+  command = "usort",
+  args = { "format", "-" },
+  stdin = true,
+  cwd = util.root_file({
+    "pyproject.toml",
+  }),
+}