Add Treesitter support to Vim upgrade (#184)

* Add `:TSUpdate` to Vim upgrade

* Reformat `freebsd.rs`

Co-authored-by: Thomas Schönauer <37108907+DottoDev@users.noreply.github.com>

src/steps/os/freebsd.rs

@@ -1,4 +1,6 @@
 use crate::command::CommandExt;
+use crate::config::Step;
+use crate::execution_context::ExecutionContext;
 use crate::executor::RunType;
 use crate::terminal::print_separator;
 use crate::utils::require_option;

src/steps/upgrade.vim

@@ -38,6 +38,14 @@ if exists(":CocUpdateSync")
     CocUpdateSync
 endif
 
+" TODO: Should this be after `PackerSync`?
+" Not sure how to sequence this after Packer without doing something weird
+" with that `PackerComplete` autocommand.
+if exists(":TSUpdate")
+    echo "TreeSitter Update"
+    TSUpdate
+endif
+
 if exists(':PackerSync')
   echo "Packer"
   autocmd User PackerComplete quitall