LS Wizard should validate the configuration options are valid JSON

[fbricon]

In a user defined LS settings page, if you put invalid json into one of the configuration fields and apply the changes, IJ will throw an exception:

Error while parsing JSON Initialization Options for the language server 'f8f5f681-d78a-4011-bab1-e583018885e2'

com.google.gson.JsonSyntaxException: java.io.EOFException: End of input at line 3 column 1 path $.provideFormatter
	at com.google.gson.internal.Streams.parse(Streams.java:59)
	at com.google.gson.JsonParser.parseReader(JsonParser.java:102)
	at com.google.gson.JsonParser.parseReader(JsonParser.java:70)
	at com.redhat.devtools.lsp4ij.server.definition.launching.UserDefinedLanguageServerDefinition.getLanguageServerInitializationOptions(UserDefinedLanguageServerDefinition.java:104)
	at com.redhat.devtools.lsp4ij.server.definition.launching.UserDefinedStreamConnectionProvider.getInitializationOptions(UserDefinedStreamConnectionProvider.java:68)
	at com.redhat.devtools.lsp4ij.LanguageServerWrapper.lambda$start$0(LanguageServerWrapper.java:326)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
	at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
Caused by: java.io.EOFException: End of input at line 3 column 1 path $.provideFormatter
	at com.google.gson.stream.JsonReader.nextNonWhitespace(JsonReader.java:1457)
	at com.google.gson.stream.JsonReader.doPeek(JsonReader.java:491)
	at com.google.gson.stream.JsonReader.hasNext(JsonReader.java:422)
	at com.google.gson.internal.bind.TypeAdapters$28.read(TypeAdapters.java:779)
	at com.google.gson.internal.bind.TypeAdapters$28.read(TypeAdapters.java:725)
	at com.google.gson.internal.Streams.parse(Streams.java:49)
	... 12 more

This should be caught before applying the changes.

[angelozerr]

IMHO I think we should have a JSON Editor or delegate that in an IJ editor.