[llvm] [docs] Fix two stale file paths (PR #213994)

[Hüseyin Kutsi Balcı via llvm-commits]

kutsibalci wrote:

Rebased onto `main` (`7380050ae`) — the branch had fallen 3024 commits behind and had started
conflicting. Worth flagging *why*, because one of the two hunks moved:

**`llvm/docs/PDB/` was converted from reStructuredText to Markdown** in the meantime, so the file the
PR edited, `PdbStream.rst`, no longer exists. The stale path survived the conversion unchanged, so
the same one-line fix now lands in `PdbStream.md:142` instead. Nothing about the finding changed —
only the file extension and the backtick style around the path.

I rebuilt the commit from freshly-fetched copies of today's `main` rather than replaying the old
diff, so nothing stale could ride along. Both findings re-verified against `7380050ae`:

| File | Says | Should say | Evidence |
|---|---|---|---|
| `HowToSubmitABug.rst:81` | `clang/utils/creduce-clang-crash.py` | `clang/utils/reduce-clang-crash.py` | renamed in 59cee030f (#128592) |
| `PdbStream.md:142` | `llvm/DebugInfo/CodeView/CVDebugRecord.h` | `llvm/include/llvm/Object/CVDebugRecord.h` | renamed in 211c67cdb |

Both replacement paths were confirmed to exist in the tree, and both source commits are recorded by
git as renames of exactly these files, so neither is a guess.

On the earlier point: the commit is authored `balcihkutsi at gmail.com`, and the account's primary
address is public, so the squashed commit will carry that address too.

*AI Tool Use Policy note: AI-assisted (Claude Code); the disclosure in the description covers the
change itself.*


https://github.com/llvm/llvm-project/pull/213994