otel.nix: trim the StartLimit comment block to the load-bearing points

Cut ~27 lines of blackout-measurement and cross-reference narrative
(already in the PR body / issue) down to the three things a reader
actually needs at this call site: the [Unit]-vs-[Service] trap, why
Restart is absent, and the window-vs-burst constraint.

nix/host-modules/otel.nix

@@ -627,35 +627,12 @@ in
       };
 
       systemd.services.opentelemetry-collector = lib.mkMerge [
-        # Survive a restart that races the outgoing process off
+        # ⚠️ `StartLimit*` are `[Unit]` settings; systemd IGNORES them under
-        # `telemetryPort`. Every deploy, the replacement collector has been
+        # `[Service]` — in `serviceConfig` they render, deploy and do
-        # reaching `bind()` while the old one still holds `127.0.0.1:8888`,
+        # nothing. `checks.module-eval-hive-otel` pins them in `unitConfig`.
-        # and nixpkgs' `Restart = "always"` with no `RestartSec` turns that
+        # `Restart` is deliberately NOT set: nixpkgs' own module defines it
-        # into the worst possible response: five retries inside two seconds,
+        # at normal priority, so a second definition is a module-system
-        # `start-limit-hit`, and no telemetry at all until something else
+        # conflict. The window must exceed `RestartSec × burst`.
-        # pokes the unit. Measured at ~27s of blackout per deploy.
-        #
-        # 🔑 Same inversion the credential wait below records — `always`
-        # reads like it makes this self-healing and does the opposite. A
-        # FAST-failing unit exhausts its allowance before the thing it is
-        # waiting for (here, an exiting process letting go of a socket) can
-        # possibly have happened. Nothing here removes that race; it makes
-        # the unit outlast it instead.
-        #
-        # Sized for a socket held by a process already on its way out —
-        # seconds, not an unseal's hours. 5s ends the blackout within one
-        # interval of the port coming free; 12 attempts ride out 55s of it
-        # being held, twice the worst gap observed. `Restart` itself is
-        # deliberately NOT set, same as both container collectors: nixpkgs'
-        # own module defines it at the normal priority, so a second
-        # definition is a conflict the module system refuses.
-        #
-        # ⚠️ `StartLimit*` are `[Unit]` settings and systemd IGNORES them
-        # under `[Service]` — written into `serviceConfig` they render,
-        # deploy and do nothing. These two options are the `[Unit]`
-        # spelling; `checks.module-eval-hive-otel` asserts they land in
-        # `unitConfig` and not beside `RestartSec`. The window has to
-        # exceed `RestartSec × burst`.
         {
           startLimitBurst = 12;
           startLimitIntervalSec = 120;