In exceptions.rakudoc, remove a CATCH keyword. Plus some stylistic improvements. (#4712)

* remove `CATCH` keyword where all that matters is the block

* fix sentence beginning & dash

* reword sentence on return value of `try` block

* remove empty line

* add space

Author: schultzdavid

doc/Language/exceptions.rakudoc

@@ -144,7 +144,7 @@ the code> in the enclosing block will never be executed.
 
 Compare with this:
 
-  CATCH {
+  {
 
     CATCH {
         default { .Str.say; }
@@ -246,7 +246,7 @@ Which would output:
       in block <unit> at exception.raku line 21
     =end code
 
-Since the C<CATCH> block is handling just the L<C<X::AdHoc>|/type/X::AdHoc> exception
+This is because the C<CATCH> block is handling just the L<C<X::AdHoc>|/type/X::AdHoc> exception
 thrown by the C<die> statement, but not the C<E> exception. In the
 absence of a C<CATCH> block, all exceptions will be contained and
 dropped, as indicated above. C<resume> will resume execution right after
@@ -255,8 +255,8 @@ Please consult the section on
 L<resuming of exceptions|/language/exceptions#Resuming_of_exceptions>
 for more information on this.
 
-A C<try>-block is a normal block and as such treats its last statement
-as the return value of itself. We can therefore use it as a right-hand
+A C<try> block is a normal block and as such, uses its last statement
+as its return value. We can therefore use it as a right-hand
 side.
 
 =begin code
@@ -388,10 +388,9 @@ sub bad-sub {
     say "Returned $return";
     CATCH {
         default {
-            say "Error ", .^name, ': ',.Str;
+            say "Error ", .^name, ': ', .Str;
             $return = '0';
             .resume;
-
         }
     }
 }