Configure IntelliJ to respect @LateInit annotations (#1606)

IntelliJ can understand that some annotations on fields mean that they
are implicitly initialized, which means we don't get the "field XXX is
not initialized" warning for `@LateInit` fields.

This setting, unfortunately, is recorded into `.idea/misc.xml`, which
contains a bunch of arbitrary stuff that we don't want to check into
source control

This adds some logic to touch up that file to mark `@LateInit` as
implicitly initialized fields, so we don't get any editor warnings.

Also, suppress some warnings.

build.gradle.kts

@@ -17,6 +17,7 @@
 import org.jetbrains.gradle.ext.ActionDelegationConfig
 import org.jetbrains.gradle.ext.ActionDelegationConfig.TestRunner.PLATFORM
 import org.jetbrains.gradle.ext.ProjectSettings
+import org.jetbrains.gradle.ext.taskTriggers
 
 plugins {
   id("pklAllProjects")
@@ -36,6 +37,8 @@ nexusPublishing {
   }
 }
 
+val configureLateInitAnnotation by tasks.registering(ConfigureLateInitAnnotation::class)
+
 idea {
   project {
     this as ExtensionAware
@@ -45,6 +48,7 @@ idea {
         delegateBuildRunToGradle = true
         testRunner = PLATFORM
       }
+      taskTriggers.afterSync(configureLateInitAnnotation)
     }
   }
 }