E5: update the warmup docs to the post-A5 behavior

A5 changed Keltner and HMA to feed their sibling sub-indicators
unconditionally, so warmup_period() is now the exact first-emission
index for every indicator. The wiki still described the old
?-starvation behavior as correct.

- Indicator-Keltner.md: the Warmup section, the worked example output
  (first emission now at i=2, not i=4), the summary table row, and the
  "reported warmup understates" pitfall now state that warmup_period()
  is exact. Example output regenerated by running the code.
- Indicator-Hma.md: the Warmup section, all three language examples
  (first Some at index 10, not 13), the table row, and the chaining
  pitfall corrected. Outputs regenerated.
- Indicators-Overview.md: dropped the claim that Hma and Kama lag their
  reported warmup — both were verified exact.

docs/wiki/Indicators-Overview.md

@@ -16,10 +16,10 @@ trait surface and warmup-period semantics are covered in
 
 The "Output range" column below is the value bounds an indicator emits once
 warm. "unbounded" means it tracks the price scale of the input. The
-"Warmup" column quotes `warmup_period()` as the indicator reports it; for
-two indicators (`Hma`, `Kama`) the practical first-emission index can lag
-the reported number because of stacked sub-indicator warmups — those
-discrepancies are noted on the deep-dive pages.
+"Warmup" column quotes `warmup_period()` as the indicator reports it; this
+is the **exact** first-emission index for every indicator — the first
+non-`None` output lands on input `warmup_period()` (index
+`warmup_period() - 1`).
 
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