Flow docs (#1432)

* Flow guide by example

* Consistent chapter naming and ordering in docs
* Make "supervision" a subsection of "Exception Handling" chapter
* Knit: filter out sampleStart/End from Knit-generated source files
* Knit: Support example auto-numbering
diff --git a/docs/select-expression.md b/docs/select-expression.md
index 35480ab..f36fa09 100644
--- a/docs/select-expression.md
+++ b/docs/select-expression.md
@@ -21,7 +21,7 @@
 
 <!--- TOC -->
 
-* [Select expression (experimental)](#select-expression-experimental)
+* [Select Expression (experimental)](#select-expression-experimental)
   * [Selecting from channels](#selecting-from-channels)
   * [Selecting on close](#selecting-on-close)
   * [Selecting to send](#selecting-to-send)
@@ -32,7 +32,7 @@
 
 
 
-## Select expression (experimental)
+## Select Expression (experimental)
 
 Select expression makes it possible to await multiple suspending functions simultaneously and _select_
 the first one that becomes available.