Add treesit-aggregated-simple-imenu-settings

Now we support setting up Imenu for multiple languages

* doc/lispref/modes.texi: Update manual.
* lisp/treesit.el:
(treesit-aggregated-simple-imenu-settings): New variable.
(treesit--imenu-merge-entries): New function.
(treesit--generate-simple-imenu): This was previously
treesit-simple-imenu.
(treesit-simple-imenu): Support
treesit-aggregated-simple-imenu-settings.
(treesit-major-mode-setup): Recognize
treesit-aggregated-simple-imenu-settings.
* test/src/treesit-tests.el (treesit-imenu): New test.

1 files changed, 9 insertions, 0 deletions

diff --git a/doc/lispref/modes.texi b/doc/lispref/modes.texi
index 73edb688c85..f227bdc635f 100644
--- a/doc/lispref/modes.texi
+++ b/doc/lispref/modes.texi
@@ -3109,6 +3109,15 @@ instead.
 automatically sets up Imenu if this variable is non-@code{nil}.
 @end defvar
 
+@defvar treesit-aggregated-simple-imenu-settings
+This variable allows major modes to configure Imenu for multiple
+languages.  Its value is an alist mapping language symbols to Imenu
+settings described in @var{treesit-simple-imenu-settings}.
+
+If both this variable and @var{treesit-simple-imenu-settings} is
+non-@code{nil}, Emacs uses this variable for setting up Imenu.
+@end defvar
+
 @node Outline Minor Mode
 @section Outline Minor Mode