implemented backslash for continuation comments

doc/manual.txt

@@ -135,6 +135,16 @@ aligned to the preceding one, it does not start a new comment:
   # statement.
   i = i + 1 # This a new comment that is NOT
   echo(i)   # continued here, because this comment refers to the echo statement
+
+
+The alignment requirement does not hold if the preceding comment piece ends in
+a backslash (followed by optional whitespace): 
+
+.. code-block:: nimrod
+  type
+    TMyObject {.final, pure, acyclic.} = object  # comment continues: \
+      # we have lots of space here to comment 'TMyObject'.
+      # This line belongs to the comment as it's properly aligned.
 
 Comments are tokens; they are only allowed at certain places in the input file
 as they belong to the syntax tree! This feature enables perfect source-to-source

doc/tut1.txt

@@ -130,6 +130,17 @@ comments need to be aligned at the same column:
   i = i + 1 # This a new comment that is NOT
   echo(i)   # continued here, because this comment refers to the echo statement
 
+
+The alignment requirement does not hold if the preceding comment piece ends in
+a backslash:
+
+.. code-block:: nimrod
+  type
+    TMyObject {.final, pure, acyclic.} = object  # comment continues: \
+      # we have lots of space here to comment 'TMyObject'.
+      # This line belongs to the comment as it's properly aligned.
+
+
 Comments are tokens; they are only allowed at certain places in the input file
 as they belong to the syntax tree! This feature enables perfect source-to-source
 transformations (such as pretty-printing) and simpler documentation generators.