v0.53.3

Fixed:

• The VS Code debug button now sources the MSVC environment before invoking fun.exe itself, not just the native C compile step - without it, fun.exe couldn't find cl.exe on PATH and silently fell back to emitting GNU-style C (__auto_type), which MSVC then rejected. The Windows fallback debugger also switched from cppdbg to cppvsdbg (reads PDB directly, no MIMode needed), and the native compile step's own cl.exe flags were corrected.
• Debug stepping into a variadic function on Windows previously landed on blank or comment lines: the synthesized varargs preamble (Vec__str vargs / va_start / va_end) had no #line directives of its own, so the C preprocessor just auto-incremented from whatever function preceded it. Every preamble line is now pinned back to the function's own declaration line.

Other:

• Removed stale FUN_CC=zig references from a couple of code comments - that workflow isn't supported or mentioned anywhere else anymore.