Read a comment after a setting's value, and off, false and no for a switch, as players mean them in nx2navi.ini.

A hand-edited "pace_smooth = 0 ; off" kept the comment in the value, which the readers took as on, "fps_limit = 144 #
monitor" gave 60, and "fullscreen = false" or "rtss = off" were on, since every reader took anything but "0" as on;
the log only named these lines (the check added for F-7). Now, for a key whose row has a set of values, cfg_load cuts
an unquoted value at the first blank followed by ';' or '#' after the '=' ("key = ; note" is unset) and logs the line
once; free text keeps its whole value (window_size, monitor, audio_device and keys without a row such as mods_dir,
pipeline_cache and the bindings, where a path or name may hold " #"), as do a value in double quotes and the
environment's values. A switch (a row whose set is 0|1) written as false, off or no reads as 0 and as true, on or yes
as 1 through cfg_get itself, so every reader agrees (cfg_bool, rt_knob, the readers that compare with "0" or parse a
number); cfg_bool and rt_knob also take those words for keys of other rows, and rt_knob no longer logs them. F-7's
check now names a switch value only when it is none of those, and a comment kept in a value only where it stays
(free text, the environment). The launcher's reader (launcher/gameini.py) cuts the same way for keys the caller
says have a set of values; its mods keys stay free text. The menu's save still writes a changed key's line again
without its comment.

This changes what existing files with such lines do, which is what was approved. tests/cfg_parse_check.py,
tests/rt_knob_check.py and launcher_test PlayerIniTest cover the cut, the words, free text, quotes and the
environment, and pass; cfg_rows_check reports 0 problems; the runtime compile check and the -Wall comparison of cfg.c
and perf.c show no new warnings.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/building.md

@@ -911,8 +911,16 @@ random frames in which the census part never passes the frame and the parts keep
 
 A change to how the on/off switches read their value (`runtime/perf.c` `rt_knob`) passes `python tests\rt_knob_check.py`,
 which cuts the function out of the file with its warning table and builds it with stand-ins for the settings and the
-log: 0, 1 and ab read as before without a line, and any other value reads as 1 and is logged once per switch. No game
-files.
+log: 0, 1 and ab read as before without a line, false, off and no in any case read as 0 and true, on and yes as 1
+without a line, and any other value reads as 1 and is logged once per switch. No game files.
+
+A change to how nx2navi.ini and the environment are read (`runtime/cfg.c` `cfg_load`, `cut_comment`, `switch_word`,
+`cfg_bool`, `check_value`) passes `python tests\cfg_parse_check.py`, which builds `cfg.c` with stand-ins for what it
+links with and loads scratch files: a comment after a value of a setting with a set of values is cut and logged once
+with its line, free text, a value in double quotes and the environment keep theirs; switches written as words read as
+0 or 1 through every reader; values outside their sets are logged with their line, at most 16 lines and a count; a
+full settings table logs one line at load and one for the menu. The launcher's reader (`launcher/gameini.py`) has the
+same comment lines in `tests\launcher_test.py` `PlayerIniTest`. No game files.
 
 The lifter (`recomp/`) and the CPU headers (`runtime/cpu.h`, `runtime/simd.h`) are checked against Unicorn. Every lifter
 change passes these, all run with `.venv`: