docs: state the validation status and correct claims the material contradicts

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docs/man/gasm-audit-instructions.1

@@ -8,12 +8,17 @@ Compare the gasm encoder for the given architecture (default amd64)
 against
 .B go tool asm
 and print the diff: superset encodings (gasm-only, shippable via
-.BR "gasm asm \-\-format goobj" ),
-known-but-unencodable names (the backlog) and go-only names (feature
-gaps).  The Go side is probed black-box with a battery of bare
-mnemonics, so the audit tracks whatever toolchain
+.BR "gasm asm \-\-format goobj" )
+and known-but-unencodable names (the backlog).  The Go side is probed
+black-box one bare mnemonic at a time, so the audit tracks whatever
+toolchain
 .B go env GOROOT
-provides.
+provides; the gasm side answers from the encoder table on amd64 and from
+trial assembly over a battery of operand shapes elsewhere.  Names
+.B go tool asm
+knows and gasm does not cannot be enumerated by probing, because Go's
+table is visible only through names already in the gasm table; the report
+closes with a note saying so rather than listing them.
 .PP
 With
 .BR \-\-corpus ,