Fix typos and markdown (#2388)

* Fix typos

* Align properly

* Update core/consensus/slots/src/lib.rs

Co-Authored-By: cmichi <mich@elmueller.net>

* Update core/network/src/test/mod.rs

Co-Authored-By: cmichi <mich@elmueller.net>

* Update core/finality-grandpa/src/communication/mod.rs

Co-Authored-By: cmichi <mich@elmueller.net>

* Update core/consensus/common/src/import_queue.rs

Co-Authored-By: cmichi <mich@elmueller.net>

substrate/core/client/src/light/blockchain.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Light client blockchin backend. Only stores headers and justifications of recent
+//! Light client blockchain backend. Only stores headers and justifications of recent
 //! blocks. CHT roots are stored for headers of ancient blocks.
 
 use std::{sync::{Weak, Arc}, collections::HashMap};

substrate/core/client/src/light/call_executor.rs

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
 
-//! Light client call exector. Executes methods on remote full nodes, fetching
+//! Light client call executor. Executes methods on remote full nodes, fetching
 //! execution proof and checking it locally.
 
 use std::{collections::HashSet, sync::Arc, panic::UnwindSafe, result, marker::PhantomData};
@@ -406,7 +406,7 @@ pub fn prove_execution<Block, S, E>(
 /// Check remote contextual execution proof using given backend.
 ///
 /// Method is executed using passed header as environment' current block.
-/// Proof shoul include both environment preparation proof and method execution proof.
+/// Proof should include both environment preparation proof and method execution proof.
 pub fn check_execution_proof<Header, E, H>(
 	executor: &E,
 	request: &RemoteCallRequest<Header>,