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/functions/recursion.bas

@@ -1,6 +1,6 @@
-10 REM A DEF call takes its environment from the pool, one per call, exactly as
+10 REM A DEF call takes an environment from the pool, one per call, exactly as
 20 REM GOSUB does. It used to be owned by the funcdef and reset on every call,
-30 REM which cost two silent defects: two calls in one expression shared a slot,
+30 REM which cost two silent defects: two calls shared a slot,
 40 REM and recursion never came back at all.
 50 DEF FACT(N#)
 60 IF N# <= 1 THEN RETURN 1
@@ -15,9 +15,9 @@
 150 DEF DBL(N#) = N# * 2
 160 PRINT DBL(10) + DBL(1)
 170 PRINT DBL(1) + DBL(10) + DBL(100)
-180 REM Depth answers to the environment pool now, so runaway recursion reports
-190 REM "Environment pool exhausted" rather than hanging. It is not exercised here
-200 REM because the statement containing a failed call still prints a junk value
-210 REM afterwards -- a separate, pre-existing defect recorded in TODO.md, and one
-220 REM this golden file would pin if it went in. tests/user_functions.c asserts
+180 REM Depth answers to the pool, so runaway recursion reports
+190 REM "Environment pool exhausted" rather than hanging. It is not exercised
+200 REM here because a failed call's statement still prints a junk value
+210 REM afterwards -- a TODO.md defect this file would pin
+220 REM if it went in. tests/user_functions.c asserts
 230 REM the message instead.