syntax_data: {"ast_node_type":"function","tokens":[{"end":59,"kind":"keyword","start":0,"text":"pub"}]}
source_snippet:     pub fn line_begin_pos(&self, pos: BytePos) -> BytePos {
context_before:     /// Returns the `BytePos` of the beginning of the current line.
context_after:         let pos = self.relative_position(pos);