Fix spelling mistakes across the whole repository (#3808)

**Update:** Pushed additional changes based on the review comments.

**This pull request fixes various spelling mistakes in this
repository.**

Most of the changes are contained in the first **3** commits:

- `Fix spelling mistakes in comments and docs`

- `Fix spelling mistakes in test names`

- `Fix spelling mistakes in error messages, panic messages, logs and
tracing`

Other source code spelling mistakes are separated into individual
commits for easier reviewing:

- `Fix the spelling of 'authority'`

- `Fix the spelling of 'REASONABLE_HEADERS_IN_JUSTIFICATION_ANCESTRY'`

- `Fix the spelling of 'prev_enqueud_messages'`

- `Fix the spelling of 'endpoint'`

- `Fix the spelling of 'children'`

- `Fix the spelling of 'PenpalSiblingSovereignAccount'`

- `Fix the spelling of 'PenpalSudoAccount'`

- `Fix the spelling of 'insufficient'`

- `Fix the spelling of 'PalletXcmExtrinsicsBenchmark'`

- `Fix the spelling of 'subtracted'`

- `Fix the spelling of 'CandidatePendingAvailability'`

- `Fix the spelling of 'exclusive'`

- `Fix the spelling of 'until'`

- `Fix the spelling of 'discriminator'`

- `Fix the spelling of 'nonexistent'`

- `Fix the spelling of 'subsystem'`

- `Fix the spelling of 'indices'`

- `Fix the spelling of 'committed'`

- `Fix the spelling of 'topology'`

- `Fix the spelling of 'response'`

- `Fix the spelling of 'beneficiary'`

- `Fix the spelling of 'formatted'`

- `Fix the spelling of 'UNKNOWN_PROOF_REQUEST'`

- `Fix the spelling of 'succeeded'`

- `Fix the spelling of 'reopened'`

- `Fix the spelling of 'proposer'`

- `Fix the spelling of 'InstantiationNonce'`

- `Fix the spelling of 'depositor'`

- `Fix the spelling of 'expiration'`

- `Fix the spelling of 'phantom'`

- `Fix the spelling of 'AggregatedKeyValue'`

- `Fix the spelling of 'randomness'`

- `Fix the spelling of 'defendant'`

- `Fix the spelling of 'AquaticMammal'`

- `Fix the spelling of 'transactions'`

- `Fix the spelling of 'PassingTracingSubscriber'`

- `Fix the spelling of 'TxSignaturePayload'`

- `Fix the spelling of 'versioning'`

- `Fix the spelling of 'descendant'`

- `Fix the spelling of 'overridden'`

- `Fix the spelling of 'network'`

Let me know if this structure is adequate.

**Note:** The usage of the words `Merkle`, `Merkelize`, `Merklization`,
`Merkelization`, `Merkleization`, is somewhat inconsistent but I left it
as it is.

~~**Note:** In some places the term `Receival` is used to refer to
message reception, IMO `Reception` is the correct word here, but I left
it as it is.~~

~~**Note:** In some places the term `Overlayed` is used instead of the
more acceptable version `Overlaid` but I also left it as it is.~~

~~**Note:** In some places the term `Applyable` is used instead of the
correct version `Applicable` but I also left it as it is.~~

**Note:** Some usage of British vs American english e.g. `judgement` vs
`judgment`, `initialise` vs `initialize`, `optimise` vs `optimize` etc.
are both present in different places, but I suppose that's
understandable given the number of contributors.

~~**Note:** There is a spelling mistake in `.github/CODEOWNERS` but it
triggers errors in CI when I make changes to it, so I left it as it
is.~~

substrate/frame/message-queue/src/lib.rs

@@ -1460,7 +1460,7 @@ impl<T: Config> Pallet<T> {
 
 /// Run a closure that errors on re-entrance. Meant to be used by anything that services queues.
 pub(crate) fn with_service_mutex<F: FnOnce() -> R, R>(f: F) -> Result<R, ()> {
-	// Holds the singelton token instance.
+	// Holds the singleton token instance.
 	environmental::environmental!(token: Option<()>);
 
 	token::using_once(&mut Some(()), || {

substrate/frame/message-queue/src/tests.rs

@@ -90,7 +90,7 @@ fn queue_priority_retains() {
 		MessageQueue::enqueue_message(msg("d"), Everywhere(2));
 		assert_ring(&[Everywhere(1), Everywhere(2), Everywhere(3)]);
 		// service head is 1, it will process a, leaving service head at 2. it also processes b but
-		// doees not empty queue 2, so service head will end at 2.
+		// does not empty queue 2, so service head will end at 2.
 		assert_eq!(MessageQueue::service_queues(2.into_weight()), 2.into_weight());
 		assert_eq!(
 			MessagesProcessed::take(),