Problem: For :InspectTree, indent size (`&shiftwidth`) for the tree
viewer may be incorrect.
This is because the tree viewer buffer with the filetype `query` does
not explicitly configures the tab size, which can mismatch with the
default indent size (2) assumed by TSTreeView's implementation.
Solution: Set shiftwidth to be the same as TSTreeViewOpts specifies,
which defaults to 2.
(cherry picked from commit 5331f87f61)
68a2259804
