Update Telemetry.pod6

Author: tisonkun

doc/Type/Telemetry.pod6

@@ -7,6 +7,8 @@
     class Telemetry { }
     class Telemetry::Period { }
 
+B<Note: > This class is a Rakudo-specific feature and not standard Perl 6.
+
 On creation, a C<Telemetry> object contains a snapshot of the current state
 of the virtual machine.  This is in itself useful, but generally one needs
 two snapshots for the difference (which is a C<Telemetry::Period> object).
@@ -22,7 +24,7 @@ use Telemetry :COLUMNS;   # imports all of the possible columns of report
 use Telemetry < cpu wallclock snap >; # only imports cpu, wallclock and snap
 =end code
 
-=head2 available data
+=head1 Available Data
 
 =item affinity-tasks-completed
 
@@ -109,7 +111,7 @@ my $t = Telemetry.new;
 say "Used $t (cpu / wallclock) microseconds to execute so far";
 =end code
 
-=head1 Additional subroutines
+=head1 Methods
 
 =head2 routine T
 
@@ -203,7 +205,7 @@ pushes.
 
 =head3 additional named parameters
 
-=item :columns
+=item C<:columns>
 
 Specify the names of the columns to be included in the report.  Names can
 be specified with the full method name (e.g. C<general-workers>) or with
@@ -214,14 +216,14 @@ If that is not set either, defaults to:
     =for code :skip-test
     wallclock util% max-rss gw gtc tw ttc aw atc
 
-=item :header-repeat
+=item C<:header-repeat>
 
 Specifies after how many lines the header should be repeated in the report.
 If not specified, defaults to what is specified in the
 C<RAKUDO_REPORT_HEADER_REPEAT> environment variable.  If that is not set either,
 defaults to 32.
 
-=item :legend
+=item C<:legend>
 
 Specifies whether a legend should be added to the report.  If not specified,
 defaults to what is specified in the C<RAKUDO_REPORT_LEGEND> environment variable.