Add while_eq macro: variable-driven loop stoppable from another mapping

[timcharper]

Problem

I wanted an autoclicker toggled on by one key and stopped by a different
key (e.g. Shift+F4 starts clicking, F4 stops it and also releases a
held button from a third mapping). toggle() doesn't fit: it only
starts/stops on a second press of the same trigger, so an unrelated
key has no way to reach it.

The natural workaround is repeat(N, if_eq($var, 1, click, wait)) driven
by a shared set()/if_eq() variable — but this runs into a sharper
problem than just "clicking never stops immediately". RepeatTask.run()
reads its count once and loops a plain for _ in range(repeats), with no
way to exit early:

https://github.com/sezanzeb/input-remapper/blob/2.2.1/inputremapper/injection/macros/tasks/repeat.py#L44-L49

Meanwhile Macro.run() refuses to start a second execution while the
first is still "running":

https://github.com/sezanzeb/input-remapper/blob/2.2.1/inputremapper/injection/macros/macro.py#L83-L87

So even after the shared variable flips to stop the clicking, the macro
instance keeps occupying that mapping's "running" slot until the fixed
repeat count exhausts — which can be minutes depending on how the count
was sized — silently swallowing every re-press of the trigger key in the
meantime. From the user's perspective: works once, then appears to just
stop responding.

Fix

while_eq(variable, value, macro) re-reads the variable every iteration
(like if_eq does) instead of deciding a count up front (like repeat
does), so run() actually returns as soon as the condition no longer
holds:

set(clicking, 1).while_eq(clicking, 1, key(BTN_LEFT).wait(50))
# a different mapping: set(clicking, 0) stops it, and the macro is
# immediately retriggerable — it isn't still "running" a leftover budget

This required a genuinely new task rather than composing existing ones —
none of repeat/hold/toggle/if_tap/if_single support an
externally-driven, unbounded, promptly-exiting loop; hold/toggle's
early-exit mechanism (press_trigger()/release_trigger()) is scoped to
the same trigger that started them, and repeat's bound is fixed at
start with no way to shorten it once running.

Changes

• inputremapper/injection/macros/tasks/while_eq.py — new task
• inputremapper/injection/macros/parse.py — registers while_eq in TASK_CLASSES
• readme/macros.md — docs entry alongside toggle
• tests/unit/test_macros/test_while_eq.py — covers: no-op when the
  condition starts false, stopping promptly when the variable is changed
  by other code mid-loop, and immediate re-triggerability after stopping

Ran the full tests/unit/test_macros suite locally (134 tests, all
passing) plus the new file on its own.

Happy to adjust naming/placement/docs wording if you'd prefer something
different — while_eq was chosen to mirror if_eq's naming rather than
introduce an unrelated verb (I'd originally called it until, which is
backwards — until conventionally means "loop while false", and this
loops while true).

[sezanzeb]

Thanks! Your implementation of while_eq mirrors the deprecated ifeq macro (variable and value arguments), and instead should probably be changed to mirror if_eq (value_1, value_2).

I fixed the lint pipeline yesterday, just merge main into your branch