Keep BASIC fixtures within the input line limit

Reflow the approved reference cases, shorten local fixture comments, and split the executable docs line so the 80-byte input buffer can read every source line.

Co-authored-by: andrew <andrew@aklabs.net>

tests/language/numeric/octal_literal.bas

@@ -1,7 +1,7 @@
-10 REM A leading zero is padding, not a radix. The reference selects base 8 for
-20 REM any lexeme starting with 0, so 010 printed 8 and 08 was a parse error --
-30 REM TODO.md section 6 item 10, fixed. Commodore BASIC has no octal literals.
-40 REM 0x is the one prefix that changes the base, and it now reaches the scanner
+10 REM A leading zero is padding, not a radix. The reference selects base 8;
+20 REM 010 printed 8 and 08 was a parse error -- TODO.md section 6 item 10.
+30 REM Commodore BASIC has no octal literals.
+40 REM 0x is the one prefix that changes the base and reaches the scanner
 50 REM whole: that was section 6 item 15.
 60 PRINT 010
 70 PRINT 08

tests/language/numeric/truth_value_arithmetic.bas

@@ -1,12 +1,12 @@
 10 REM A truth value carries its payload in boolvalue, not floatval. The three
 20 REM numeric operators were `if ( INTEGER ) ... else <treat as float>`, and
-30 REM that else was a catch-all rather than a float branch -- so a truth value
+30 REM that else was a catch-all, not a float branch -- so a truth value
 40 REM on the LEFT computed 0 - 1 into a field nothing reads, kept its BOOLEAN
 50 REM type, and printed `true` instead of -2. Silent, and wrong twice over.
 60 A# = 1
 70 PRINT (A# == 1)
-80 REM On the RIGHT it stays legal and stays -1, which is the same property that
-90 REM lets AND and OR double as logical operators. Refusing it here would have
+80 REM On the RIGHT it stays legal and stays -1, the same property that
+90 REM lets AND and OR double as logical operators. Refusing it would have
 100 REM broken every condition in the language.
 110 PRINT 5 - (A# == 1)
 120 PRINT 5 * (A# == 1)