Add more details to "Submodules" in CONTRIBUTING.md (realm#1280)

The reason to checkout git submodules wasn't mentioned. I added the use cases for submodules, as Swift Package Manager doesn't make use of the git submodules.
mknabbe · Oct 27, 2020 · f697b6f · f697b6f
1 parent 84023e6
commit f697b6f
Showing 1 changed file with 5 additions and 3 deletions.
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -38,9 +38,11 @@ Then you can use the full power of Xcode/LLDB/Instruments to develop and debug y
 ### Submodules
 
 This SwiftLint repository uses submodules for its dependencies.
-This means that if you decide to fork this repository to contribute to SwiftLint,
-don't forget to checkout the submodules as well when cloning, by running
-`git submodule update --init --recursive` after cloning.
+The git submodules are used when using the Xcode project and workspace
+(e.g. `xed SwiftLint.xcworkspace`) and building SwiftLint by executing
+the `Makefile`. This means that if you decide to fork this repository to
+contribute to SwiftLint, don't forget to checkout the submodules as well when
+cloning, by running `git submodule update --init --recursive` after cloning.
 
 See more info [in the README](https://github.com/realm/SwiftLint#installation).