add formatter config for yamlfix and clang-format

clang-format's built in styles REALLY all suck quite badly. how the
fuck is it possible that this tool can be made with builtin styles
that offer very little in the way of variety? jesus christ ...

lua/plugins/conform.lua

@@ -35,11 +35,20 @@ return {
       end,
       formatters_by_ft = {
         lua = { 'stylua' },
-        -- Conform can also run multiple formatters sequentially
-        -- python = { "isort", "black" },
-        --
-        -- You can use 'stop_after_first' to run the first available formatter from the list
-        -- javascript = { "prettierd", "prettier", stop_after_first = true },
+        yaml = { 'yamlfmt' },
+        c = { 'clang-format' },
+      },
+      formatters = {
+        ['yamlfmt'] = {
+          prepend_args = { '-formatter', 'retain_line_breaks_single=true,trim_trailing_whitespace=true' },
+        },
+        -- all of the builtin clang-format styles are pretty bad IMHO. don't fallback to any.
+        -- unfortunately, `--fallback-style` doesn't allow inline customization like the
+        -- `--style` option does.
+        -- i really can't say that i'm impressed with clang-format overall ...
+        ['clang-format'] = {
+          prepend_args = { '--style=file', '--fallback-style=none' },
+        },
       },
     },
   },