When I added the log structure to `build/logMessage` in #2022 I must have assumed that the entire BSP notifciation was an extension defined by SourceKit-LSP and didn’t realized that this was actually a change that made the notification non-compliant with BSP. Change it up a little bit to make it compliant again.
The term *build system* predated our wide-spread adoption of BSP for communicating between SourceKit-LSP to the build system and was never really the correct term anyway – ie. a `JSONCompilationDatabaseBuildSystem` never really sounded right. We now have a correct term for the communication layer between SourceKit-LSP: A build server. Rename most occurrences of *build system* to *build server* to reflect this. There are unfortunately a couple lingering instances of *build system* that we can’t change, most notably: `fallbackBuildSystem` in the config file, the `workspace/waitForBuildSystemUpdates` BSP extension request and the `synchronize-for-build-system-updates` experimental feature.
