bug#75079: Default parser for treesit-explore

[Juri Linkov]

Currently loading the desktop is disrupted by the prompt
that asks for a parser name when treesit-explore-mode
was enabled in a buffer before.  The second part of the
following patch fixes this by omitting treesit-explore-mode.

But anyway it's very tedious to select the single parser
every time when enabling treesit-explore-mode.  So the
first part of this patch avoids this unnecessary selection:

diff --git a/lisp/treesit.el b/lisp/treesit.el
index 464b7e688be..5428e84fa5a 100644
--- a/lisp/treesit.el
+++ b/lisp/treesit.el
@@ -3911,8 +3911,10 @@ treesit-explorer-switch-parser
   (interactive
    (list (let* ((parser-alist
                  (treesit--explorer-generate-parser-alist))
-                (parser-name (completing-read
-                              "Parser: " (mapcar #'car parser-alist))))
+                (parser-name (if (= (length parser-alist) 1)
+                                 (car parser-alist)
+                               (completing-read
+                                "Parser: " (mapcar #'car parser-alist)))))
            (alist-get parser-name parser-alist
                       nil nil #'equal))))
   (unless treesit-explore-mode
@@ -3952,7 +3954,13 @@ treesit-explore-mode
           (unless (memq 'treesit--explorer-tree-mode
                         desktop-modes-not-to-save)
             (push 'treesit--explorer-tree-mode
-                  desktop-modes-not-to-save))))
+                  desktop-modes-not-to-save)))
+        ;; Tell `desktop-save' to not save minor mode.
+        (when (boundp 'desktop-minor-mode-table)
+          (unless (member '(treesit-explore-mode nil)
+                          desktop-minor-mode-table)
+            (push '(treesit-explore-mode nil)
+                  desktop-minor-mode-table))))
     ;; Turn off explore mode.
     (remove-hook 'post-command-hook
                  #'treesit--explorer-post-command t)