add docs to SmartKeyRWLocker and SmartRWLocker

coroutines/src/commonMain/kotlin/dev/inmo/micro_utils/coroutines/SmartKeyRWLocker.kt

@@ -7,6 +7,22 @@ import kotlin.contracts.ExperimentalContracts
 import kotlin.contracts.InvocationKind
 import kotlin.contracts.contract
 
+/**
+ * Combining [globalRWLocker] and internal map of [SmartRWLocker] associated by [T] to provide next logic:
+ *
+ * * Locker by key, for reading: waiting for [globalRWLocker] unlock write by acquiring read permit in it and then
+ * taking or creating locker for key [T] and lock its reading too
+ * * Locker by key, for writing: waiting for [globalRWLocker] unlock write by acquiring read permit in it and then
+ * taking or creating locker for key [T] and lock its writing
+ * * [globalRWLocker], for reading: using [SmartRWLocker.acquireRead], will be suspended until its
+ * [SmartRWLocker.lockWrite] will not be unlocked
+ * * [globalRWLocker], for writing: using [SmartRWLocker.lockWrite], will be paused by other reading and writing
+ * operations and will pause other operations until the end of operation (calling of [unlockWrite])
+ *
+ * You may see, that lockers by key still will use global locker permits - it is required to prevent [globalRWLocker]
+ * write locking during all other operations are not done. In fact, all the keys works like a simple [SmartRWLocker] as
+ * well, as [globalRWLocker], but they are linked with [globalRWLocker] [SmartRWLocker.acquireRead] permissions
+ */
 class SmartKeyRWLocker<T>(
     globalLockerReadPermits: Int = Int.MAX_VALUE,
     globalLockerWriteIsLocked: Boolean = false,

coroutines/src/commonMain/kotlin/dev/inmo/micro_utils/coroutines/SmartRWLocker.kt

@@ -8,9 +8,10 @@ import kotlin.contracts.contract
 /**
  * Composite mutex which works with next rules:
  *
- * * [acquireRead] require to [writeMutex] be free. Then it will take one lock from [readSemaphore]
+ * * [acquireRead] require to [writeMutex] to be free. Then it will take one lock from [readSemaphore]
  * * [releaseRead] will just free up one permit in [readSemaphore]
- * * [lockWrite] will lock [writeMutex] and then await while all [readSemaphore] will be freed
+ * * [lockWrite] will lock [writeMutex] and then await while all [readSemaphore] will be freed. If coroutine will be
+ * cancelled during read semaphore freeing, locking will be cancelled too with [SmartMutex.Mutable.unlock]ing of [writeMutex]
  * * [unlockWrite] will just unlock [writeMutex]
  */
 class SmartRWLocker(private val readPermits: Int = Int.MAX_VALUE, writeIsLocked: Boolean = false) {