Bump richtextfx from 0.9.1 to 0.9.2 (#4512)

Bumps [richtextfx](https://github.com/FXMisc/RichTextFX) from 0.9.1 to 0.9.2.
- [Release notes](https://github.com/FXMisc/RichTextFX/releases)
- [Changelog](https://github.com/FXMisc/RichTextFX/blob/master/CHANGELOG.md)
- [Commits](FXMisc/RichTextFX@v0.9.1...v0.9.2)

Signed-off-by: dependabot[bot] <support@dependabot.com>

build.gradle

@@ -133,7 +133,7 @@ dependencies {
     compile 'de.saxsys:mvvmfx:1.7.0'
     compile 'org.fxmisc.easybind:easybind:1.0.3'
     compile 'org.fxmisc.flowless:flowless:0.6.1'
-    compile 'org.fxmisc.richtext:richtextfx:0.9.1'
+    compile 'org.fxmisc.richtext:richtextfx:0.9.2'
     compile 'com.sibvisions.external.jvxfx:dndtabpane:0.1'
     compile 'javax.inject:javax.inject:1'
     compile 'com.jfoenix:jfoenix:8.0.7'