[documentation] Fix a few typos and add some remarks

docs/src/building.md

@@ -431,7 +431,7 @@ different meanings:
 
 As a package developer, you may want to test JLL packages locally, or as a binary dependency
 developer you may want to easily use custom binaries.  Through a combination of `dev`'ing out
-the JLL package and creating an `overrides` directory, it is easy to get complete control over
+the JLL package and creating an `override` directory, it is easy to get complete control over
 the local JLL package state.
 
 ## Overriding a prebuilt JLL package's binaries
@@ -471,6 +471,11 @@ the `~/.julia/dev/` directory, but it will not be uploaded anywhere.  This is
 useful for local testing and validation that the built artifacts are working
 with your package.
 
+If you want to build a JLL package only for your current platform,
+you can use `platforms = [HostPlatform()]` in the `build_tarball.jl` script.
+You can also provide the target triplet `Base.BinaryPlatforms.host_triplet()`
+if you run the script in the command line.
+
 ## Deploying local builds without recreating the tarballs
 Sometimes all tarballs have already been created successfully locally but not
 deployed to GitHub. This can happen, e.g., if it is tricky to figure out the

docs/src/index.md

@@ -47,7 +47,7 @@ If you decide to use this workflow, however, you will need to manually open pull
 
 ### GitHub Codespaces
 
-If you already have access to the [GitHub Codespaces](https://github.com/features/codespaces) service, you can use use BinaryBuilder and all the workflows described above in your browser or with Visual Studio Code, on any operating system, including those not natively supported by the package!  Head to [Yggdrasil](https://github.com/JuliaPackaging/Yggdrasil/) and create a new Codespace.
+If you already have access to the [GitHub Codespaces](https://github.com/features/codespaces) service, you can use BinaryBuilder and all the workflows described above in your browser or with Visual Studio Code, on any operating system, including those not natively supported by the package!  Head to [Yggdrasil](https://github.com/JuliaPackaging/Yggdrasil/) and create a new Codespace.
 
 ## How does this all work?
 

docs/src/jll.md

@@ -231,6 +231,11 @@ package, depending on whether the package is `dev`'ed or not.  The second method
 is particularly recommended to system administrator who wants to use system
 libraries in place of the libraries in JLL packages.
 
+!!! warning
+    The `Artifacts.toml` of the overridden JLL packages must have valid url
+    fields because Julia always installs an artifact for your platform
+    even if you override it. This impacts locally built JLL packages.
+
 ### `dev`'ed JLL packages
 
 In the event that a user wishes to override the content within a `dev`'ed JLL
@@ -306,4 +311,3 @@ Note that the product name is `libbzip2`, but we use `libbzip2_path`.
        build. Please open an issue on [Yggdrasil](https://github.com/JuliaPackaging/Yggdrasil/)
        requesting a new build, or make a pull request to update the relevant
        `build_tarballs.jl` script.
-