Add Override Your Project Mise File as a Mise TIL

mise/override-your-project-mise-file.md

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+# Override Your Project Mise File
+
+A project I'm working on has a version-controlled `.mise.toml` file in it. Some
+changes were made to that recently that introduce some env vars that conflict
+with my setup. If I make edits to that file, then I have a modified version of
+`.mise.toml` sitting in my Git working copy.
+
+```
+# .mise.toml
+[env]
+CONFIG_SETTING = "project"
+```
+
+Instead, I can rely on the loading precedence rules of `mise` to override those
+project settings with my individual settings. I can do that with the
+`.mise.local.toml` file which is played on top of any `mise` configuration from
+files further down the precedence chain.
+
+```
+# .mise.local.toml
+[env]
+CONFIG_SETTING = "override"
+```
+
+Assuming I have `mise` setup with my shell environment to automatically load in
+these files, I can now check what takes precedence:
+
+```bash
+$ echo $CONFIG_SETTING
+override
+```
+
+Make sure `.mise.local.toml` is included in the `.gitignore` file to avoid
+checking in your personal environment overrides.
+
+To be sure about what files are loaded and in what order, give `mise cfg` a try.
+I discuss that in more detail in [List The Files Being Loaded By Mise](list-the-files-being-loaded-by-mise.md).