[LLDB] Increase level of headings in lldb-dap docs (#175519)
The lldb-dap docs had more than one top-level heading (one `#`). All top
level headings are shown in the "Using LLDB" list on the left side. In
this case, "Supported Features" and "Configuration Settings Reference"
showed up there.
With this PR, these headings are increased by one level. This also
increases the level of "Debug Console" (child of "Supported Features")
and "Common/Launch/Attach configurations" (child of "Configuration
Settings Reference").