…nored

this commit fixes the vim.treesitter.get_node_text from ignoring the
offset and possibly other directives like gsub as well.

the reason for this change is that metadata in query:iter_captures was
only available if the capture_id is 1 and was reset to an empty table
for the captures after that but wasn't replenished and remained empty.

assume that you have a treesitter injection in a rust macro. here's what
it would look like

(macro_invocation
 (scoped_identifier
    path: (identifier) @path (#eq? @path "sqlx")
    name: (identifier) @name (#match? @name "^query.*")
 )

 (token_tree
    (raw_string_literal) @injection.content
    (#set! injection.language "sql")
    (#set! injection.include-children)
 )
 (#offset! @injection.content 0 3 0 -2)
)

a raw string in rust looks like this r#"select * from "user";"#

in the #offset! directive raw string start and end identifiers
(#r" and "#) are offsetted and what remains is the inner sql.

this offset information is set to the metadata for query.get_node_text
to use.

however, it's not available when it needs to be used.
in query:iter_captures you get @path capture first then you get @name
capture and finally @injection.content capture. metadata is only
available in @path capture. which is when the capture_id is 1

this commit sets this to an outside variable and makes it always available.

maybe treesitter needs to fix this as a bug. I don't know honestly.