Improve structure

doc/Type/Backtrace.pod6

@@ -77,16 +77,20 @@ Defined as:
 Returns a summary string representation of the backtrace, filtered
 by C<!.is-hidden && (.is-routine || !.is-setting)>.
 
-    this program:
+This program:
+
     sub inner { say Backtrace.new.summary }
     sub outer { inner; }
     outer;
 
-    results in:
-    in method new at SETTING::src/core/Backtrace.pm6 line 85
-    in sub inner at test.p6 line 1
-    in sub outer at test.p6 line 2
-    in block <unit> at test.p6 line 3
+results in:
+
+=for code :lang<text>
+in method new at SETTING::src/core/Backtrace.pm6 line 85
+in sub inner at test.p6 line 1
+in sub outer at test.p6 line 2
+in block <unit> at test.p6 line 3
+
 
 =head2 method concise
 
@@ -97,14 +101,17 @@ Defined as:
 Returns a concise string representation of the backtrace, filtered
 by C<!.is-hidden && .is-routine && !.is-setting>.
 
-    this program:
+This program:
+
     sub inner { say Backtrace.new.concise }
     sub outer { inner; }
     outer;
 
-    results in:
-    in sub inner at test.p6 line 1
-    in sub outer at test.p6 line 2
+results in:
+
+=for code :lang<text>
+in sub inner at test.p6 line 1
+in sub outer at test.p6 line 2
 
 =head2 method map
 
@@ -114,18 +121,21 @@ Defined as:
 
 It invokes &code for each element and gathers the return values in a sequence and returns it.
 
-    this program:
+This program:
+
     sub inner { Backtrace.new.map({ say "{$_.file}: {$_.line}" }); }
     sub outer { inner; }
     outer;
 
-    results in:
-    SETTING::src/core/Backtrace.pm6: 85
-    SETTING::src/core/Backtrace.pm6: 85
-    test.p6: 1
-    test.p6: 2
-    test.p6: 3
-    test.p6: 1
+results in:
+
+=for code :lang<text>
+SETTING::src/core/Backtrace.pm6: 85
+SETTING::src/core/Backtrace.pm6: 85
+test.p6: 1
+test.p6: 2
+test.p6: 3
+test.p6: 1
 
 =head2 method flat
 
@@ -137,4 +147,4 @@ Returns the backtrace same as L<list|#method_list>.
 
 =end pod
 
-# vim: expandtab softtabstop=4 shiftwidth=4 ft=perl6
+# vim: expandtab softtabstop=4 shiftwidth=4 ft=perl6