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/client/network/sync/src/strategy.rs

@@ -185,7 +185,7 @@ where
 		+ Sync
 		+ 'static,
 {
-	/// Initialize a new syncing startegy.
+	/// Initialize a new syncing strategy.
 	pub fn new(
 		config: SyncingConfig,
 		client: Arc<Client>,
@@ -418,7 +418,7 @@ where
 			self.state.is_some() ||
 			match self.chain_sync {
 				Some(ref s) => s.status().state.is_major_syncing(),
-				None => unreachable!("At least one syncing startegy is active; qed"),
+				None => unreachable!("At least one syncing strategy is active; qed"),
 			}
 	}
 
@@ -429,7 +429,7 @@ where
 
 	/// Returns the current sync status.
 	pub fn status(&self) -> SyncStatus<B> {
-		// This function presumes that startegies are executed serially and must be refactored
+		// This function presumes that strategies are executed serially and must be refactored
 		// once we have parallel strategies.
 		if let Some(ref warp) = self.warp {
 			warp.status()
@@ -438,7 +438,7 @@ where
 		} else if let Some(ref chain_sync) = self.chain_sync {
 			chain_sync.status()
 		} else {
-			unreachable!("At least one syncing startegy is always active; qed")
+			unreachable!("At least one syncing strategy is always active; qed")
 		}
 	}
 
@@ -518,7 +518,7 @@ where
 
 	/// Proceed with the next strategy if the active one finished.
 	pub fn proceed_to_next(&mut self) -> Result<(), ClientError> {
-		// The strategies are switched as `WarpSync` -> `StateStartegy` -> `ChainSync`.
+		// The strategies are switched as `WarpSync` -> `StateStrategy` -> `ChainSync`.
 		if let Some(ref mut warp) = self.warp {
 			match warp.take_result() {
 				Some(res) => {
@@ -569,7 +569,7 @@ where
 				},
 			}
 		} else if let Some(state) = &self.state {
-			if state.is_succeded() {
+			if state.is_succeeded() {
 				info!(target: LOG_TARGET, "State sync is complete, continuing with block sync.");
 			} else {
 				error!(target: LOG_TARGET, "State sync failed. Falling back to full sync.");