Tweak __fastfail termination note text to clarify behavior

Author: vangata-ve

compiler/rustc_codegen_ssa/messages.ftl

@@ -176,7 +176,7 @@ codegen_ssa_ld64_unimplemented_modifier = `as-needed` modifier not implemented y
 
 codegen_ssa_lib_def_write_failure = failed to write lib.def file: {$error}
 
-codegen_ssa_link_exe_fastfail_abort_note = This may be caused by Windows `__fastfail` termination, such as an `abort()` call, and does not necessarily indicate a stack buffer overrun.
+codegen_ssa_link_exe_fastfail_abort_note = This may occur when using the MSVC toolchain on Windows and can be caused by `__fastfail` termination, rather than necessarily indicating a stack buffer overrun.
 
 codegen_ssa_link_exe_fastfail_status = 0xc0000409 is `STATUS_STACK_BUFFER_OVERRUN`