Emit Symbol Graphs and add go-to-definition support for Markdown and Tutorial files

[Padmashree06]

This PR introduces go-to-definition support for Markdown and Tutorial files.

To enable this functionality, symbol graphs are now emitted during both the initial build and background indexing. The generated symbol graph data is then used to resolve symbols referenced in documentation files and navigate to their corresponding source definitions.

Changes

• Emit symbol graphs during the initial build.
• Emit symbol graphs during background indexing.
• Add go-to-definition support for Markdown and Tutorial files using the generated symbol graph data.

User Impact

Users can now invoke go-to-definition on symbols referenced in Markdown and Tutorial files and navigate to the corresponding source definition.