docs(doc.go): name MaxConcurrent for ConcurrencyConcurrent in Dispatch Modes (#89)

Rewrites the Dispatch Modes concurrency paragraph: drop/queue/debounce/burst serialize per lock scope; ConcurrencyConcurrent takes no lock and is bounded by RuntimeOptions.MaxConcurrent slots per instance, and a waiting event is ignored if its context ends first.

Closes #88

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Author: ThomasK33

doc.go

@@ -95,11 +95,14 @@
 // before dedupe marking, so the platform's retry is not mistaken for a
 // duplicate.
 //
-// [RuntimeOptions].Concurrency decides what happens to an event that arrives
-// while a handler holds its lock scope, which is one thread by default or the
-// whole channel with [LockScopeChannel]: [ConcurrencyDrop] (the default),
-// [ConcurrencyQueue], [ConcurrencyDebounce], [ConcurrencyConcurrent], or
-// [ConcurrencyBurst]. Debounce and burst require deferred dispatch.
+// [RuntimeOptions].Concurrency decides how overlapping events are handled.
+// [ConcurrencyDrop] (the default), [ConcurrencyQueue], [ConcurrencyDebounce],
+// and [ConcurrencyBurst] serialize handlers per lock scope, which is one
+// thread by default or the whole channel with [LockScopeChannel]; debounce
+// and burst require deferred dispatch. [ConcurrencyConcurrent] takes no lock
+// and ignores the lock scope: [RuntimeOptions].MaxConcurrent, which must be
+// positive, caps simultaneous handlers per instance, and an event that finds
+// every slot busy waits for one and is ignored if its context ends first.
 //
 // [WithRuntimeOptions] replaces the whole options struct, so start from
 // [DefaultRuntimeOptions] and change only the fields you need.