feat(treesitter)!: don't parse tree in get_parser() or start()

**Problem:** `vim.treesitter.get_parser()` and `vim.treesitter.start()`
both parse the tree before returning it. This is problematic because if
this is a sync parse, it will stall the editor on large files. If it is
an async parse, the functions return stale trees.

**Solution:** Remove this parsing side effect and leave it to the user
to parse the returned trees, either synchronously or asynchronously.

1 files changed, 7 insertions, 5 deletions

diff --git a/test/functional/treesitter/parser_spec.lua b/test/functional/treesitter/parser_spec.lua
index 6f9faddbe3..825c2b8f29 100644
--- a/test/functional/treesitter/parser_spec.lua
+++ b/test/functional/treesitter/parser_spec.lua
@@ -1142,11 +1142,13 @@ print()
       feed(':set ft=help<cr>')
 
       exec_lua(function()
-        vim.treesitter.get_parser(0, 'vimdoc', {
-          injections = {
-            vimdoc = '((codeblock (language) @injection.language (code) @injection.content) (#set! injection.include-children))',
-          },
-        })
+        vim.treesitter
+          .get_parser(0, 'vimdoc', {
+            injections = {
+              vimdoc = '((codeblock (language) @injection.language (code) @injection.content) (#set! injection.include-children))',
+            },
+          })
+          :parse()
       end)
     end)