hex_exponent      = ( "p" | "P" ) [ "+" | "-" ] decimal_digits .
</pre>

<pre>
0.
72.40
072.40       // == 72.40
2.71828
1.e+0
6.67428e-11
1E6
.25
.12345E+5
1_5.         // == 15.0
0.15e+0_2    // == 15.0

0x1p-2       // == 0.25
0x2.p10      // == 2048.0
0x1.Fp+0     // == 1.9375
0X.8p-0      // == 0.5
0X_1FFFP-16  // == 0.1249847412109375

For example, if the directory `6-stdlib/99-minor` is present,
then an `api/next` file with the line

    pkg net/http, function F #12345

should have a corresponding file named `doc/next/6-stdlib/99-minor/net/http/12345.md`.
At a minimum, that file should contain either a full sentence or a TODO,
ideally referring to a person with the responsibility to complete the note.

	MOVD $-32768, R6                // 38c08000
	MOVD $1234567, R5               // 6405001260a5d687 or 0600001238a0d687
	MOVW $1, R3                     // 38600001
	MOVW $-1, R4                    // 3880ffff
	MOVW $65535, R5                 // 6005ffff
	MOVW $65536, R6                 // 3cc00001
	MOVW $-32767, R5                // 38a08001
	MOVW $-32768, R6                // 38c08000
	MOVW $1234567, R5               // 6405001260a5d687 or 0600001238a0d687

	MOVF	$8(SP), X5			// ERROR "unsupported address load"
	MOV	$1234, 0(SP)			// ERROR "constant load must target register"
	MOV	$1234, 8(SP)			// ERROR "constant load must target register"
	MOV	$0, 0(SP)			// ERROR "constant load must target register"
	MOV	$0, 8(SP)			// ERROR "constant load must target register"
	MOV	$1234, 0(SP)			// ERROR "constant load must target register"
	MOV	$1234, 8(SP)			// ERROR "constant load must target register"

type TitleTest struct {
	in, out string
}

var TitleTests = []TitleTest{
	{"", ""},
	{"a", "A"},
	{" aaa aaa aaa ", " Aaa Aaa Aaa "},
	{" Aaa Aaa Aaa ", " Aaa Aaa Aaa "},
	{"123a456", "123a456"},
	{"double-blind", "Double-Blind"},
	{"ÿøû", "Ÿøû"},
	{"with_underscore", "With_underscore"},
	{"unicode \xe2\x80\xa8 line separator", "Unicode \xe2\x80\xa8 Line Separator"},
}

//		outcode($1, $2, &$5, int32($3.Reg), &$7);
//	}
	STREX	R1, (R2), R3 // STREX (R2), R1, R3

//
// word
//
//	LTYPEH comma ximm
//	{
//		outcode($1, Always, &nullgen, 0, &$3);
//	}
	WORD	$1234

//
// floating-point coprocessor
//
//	LTYPEI cond freg ',' freg
//	{
//		outcode($1, $2, &$3, 0, &$5);
//	}
	ABSF	F1, F2

//	LTYPEK cond frcon ',' freg
//	{

hex_exponent      = ( "p" | "P" ) [ "+" | "-" ] decimal_digits .
</pre>

<pre>
0.
72.40
072.40       // == 72.40
2.71828
1.e+0
6.67428e-11
1E6
.25
.12345E+5
1_5.         // == 15.0
0.15e+0_2    // == 15.0

0x1p-2       // == 0.25
0x2.p10      // == 2048.0
0x1.Fp+0     // == 1.9375
0X.8p-0      // == 0.5
0X_1FFFP-16  // == 0.1249847412109375

The [Alias] type now has an [Rhs] method that returns the type on the
right-hand side of its declaration: given `type A = B`, the `Rhs` of A