Fix some busted escape sequences in docs, and slightly reformat a few examples

doc_src/bind.txt

@@ -109,7 +109,7 @@ The following special input functions are available:
 \subsection bind-example Examples
 
 \fish
-bind \cd 'exit'
+bind \\cd 'exit'
 \endfish
 Causes `fish` to exit when @key{Control,D} is pressed.
 
@@ -120,6 +120,6 @@ Performs a history search when the @key{Page Up} key is pressed.
 
 \fish
 set -g fish_key_bindings fish_vi_key_bindings
-bind -M insert \cc kill-whole-line force-repaint
+bind -M insert \\cc kill-whole-line force-repaint
 \endfish
 Turns on Vi key bindings and rebinds @key{Control,C} to clear the input line.

doc_src/echo.txt

@@ -51,8 +51,10 @@ If `-e` is used, the following sequences are recognized:
 
 \fish
 echo 'Hello World'
-# Print hello world to stdout
-
-echo -e 'Top\nBottom'
-# Print Top and Bottom on separate lines, using an escape sequence
 \endfish
+Print hello world to stdout
+
+\fish
+echo -e 'Top\\nBottom'
+\endfish
+Print Top and Bottom on separate lines, using an escape sequence