fix(treesitter): offset directive associates range with capture (#18276)

Previously the `offset!` directive populated the metadata in such a way
that the new range could be attributed to a specific capture. #14046
made it so the directive simply stored just the new range in the
metadata and information about what capture the range is based from is
lost.

This change reverts that whilst also correcting the docs.

1 files changed, 16 insertions, 5 deletions

diff --git a/runtime/lua/vim/treesitter/languagetree.lua b/runtime/lua/vim/treesitter/languagetree.lua
index 57d8c5fd21..5a05a29da8 100644
--- a/runtime/lua/vim/treesitter/languagetree.lua
+++ b/runtime/lua/vim/treesitter/languagetree.lua
@@ -295,6 +295,14 @@ function LanguageTree:included_regions()
   return self._regions
 end
 
+---@private
+local function get_node_range(node, id, metadata)
+  if metadata[id] and metadata[id].range then
+    return metadata[id].range
+  end
+  return { node:range() }
+end
+
 --- Gets language injection points by language.
 ---
 --- This is where most of the injection processing occurs.
@@ -327,10 +335,10 @@ function LanguageTree:_get_injections()
 
         -- Allow for captured nodes to be used
         if type(content) == 'number' then
-          content = { match[content] }
+          content = { match[content]:range() }
         end
 
-        if content then
+        if type(content) == 'table' and #content >= 4 then
           vim.list_extend(ranges, content)
         end
       end
@@ -351,7 +359,7 @@ function LanguageTree:_get_injections()
         elseif name == 'combined' then
           combined = true
         elseif name == 'content' and #ranges == 0 then
-          table.insert(ranges, node)
+          table.insert(ranges, get_node_range(node, id, metadata))
           -- Ignore any tags that start with "_"
           -- Allows for other tags to be used in matches
         elseif string.sub(name, 1, 1) ~= '_' then
@@ -360,7 +368,7 @@ function LanguageTree:_get_injections()
           end
 
           if #ranges == 0 then
-            table.insert(ranges, node)
+            table.insert(ranges, get_node_range(node, id, metadata))
           end
         end
       end
@@ -397,7 +405,10 @@ function LanguageTree:_get_injections()
 
       for _, entry in pairs(patterns) do
         if entry.combined then
-          table.insert(result[lang], vim.tbl_flatten(entry.regions))
+          local regions = vim.tbl_map(function(e)
+            return vim.tbl_flatten(e)
+          end, entry.regions)
+          table.insert(result[lang], regions)
         else
           for _, ranges in ipairs(entry.regions) do
             table.insert(result[lang], ranges)