Update IntelliJ Rust info

Completion and Goto Definition more or less work now. Quick documentation also works.

References: 

Documentation: https://intellij-rust.github.io/features/

Demo: https://intellij-rust.github.io/docs/quick-start.html#project-ready

table.jade

@@ -143,11 +143,11 @@ table#overview
       td.highlighting ✓<sup>1</sup>
       //-td.tomlhighlighting
       td.snippets ✓<sup>1</sup>
-      td.completion
+      td.completion ✓<sup>1</sup>
       td.linting
-      td.goto
+      td.goto ✓<sup>1</sup>
       td.debugging
-      td.doctooltips
+      td.doctooltips ✓<sup>1</sup>
     tr
       th.name
         a(href="#visualstudio") Visual Studio