Fix stale comments referencing deleted launchers

Summary:
Doc/comment-only cleanup of references to the now-deleted `offline_postmortem` and `tintype_debug_launcher` binaries.

- `tintype/fb/runtime_paths.py`: drop the `offline_postmortem` / serialization mentions from the docstring; `get_runtime_path` is now shared only with the debugpy adapter.
- `tintype/dap/cli.py`: remove the "separate from the legacy pydevd-based `tintype_debug_launcher`" sentence.
- `tintype/fb/BUCK`: reword the `tintype_dap_server` comment that referenced matching `tintype_debug_launcher`.
- `tintype/snapshot_lib/SnapshotReader.cpp`: reword the mkstemp comment's example (a sibling process reading the same `.pytb`) which named `tintype_debug_launcher`.

No behavior change.

Reviewed By: piyushjaiswal98

Differential Revision: D114678766

fbshipit-source-id: a5f49c5142b1001aeb79bfbfd729953e194b302d

Author: pdepetro

dap/cli.py

@@ -7,9 +7,7 @@
 """CLI entry point for the tintype DAP server.
 
 Dedicated binary (``tintype_dap_server``) that serves a ``.pytb``
-snapshot over the Debug Adapter Protocol.  Separate from the legacy
-pydevd-based ``tintype_debug_launcher`` so the two flows don't share a
-dispatch branch.
+snapshot over the Debug Adapter Protocol.
 
 Transport:
 

snapshot_lib/SnapshotReader.cpp

@@ -153,9 +153,9 @@ bool SnapshotReader::open(const std::string& path) {
 
     // Create a unique temporary file for the decompressed data.
     // mkstemp guarantees a fresh path so concurrent readers of the same
-    // compressed source file (e.g., a sibling process attaching
-    // tintype_debug_launcher to the same .pytb) cannot collide on this temp
-    // file. With a shared name, one reader's O_TRUNC + ftruncate corrupts
+    // compressed source file (e.g., a sibling process reading the same
+    // .pytb) cannot collide on this temp file. With a shared name, one
+    // reader's O_TRUNC + ftruncate corrupts
     // another reader's MAP_SHARED mmap (zero-fills the buffer through the
     // shared inode) — see SnapshotWriter::open which already uses mkstemp
     // for the same reason.