Add Single And Double Quoted String Notation as a ruby til

ruby/single-and-double-quoted-string-notation.md

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+# Single And Double Quoted String Notation
+
+If you are building a string that involves interpolation and literal double
+quotes, then you'll have to do some escaping. Here is an example:
+
+```ruby
+> feet, inches = [6, 4]
+> puts "I am #{feet}'#{inches}\" tall"
+I am 6'4" tall
+```
+
+Having to escape a single instance of a double quote isn't so bad. If you find
+yourself having to do it a bunch, Ruby has something for you. It is a string
+syntax feature called [Percent Notation](percent-notation.md).
+
+You can use percent notation to define double-quoted strings using `Q`:
+
+```ruby
+> puts %Q[I am #{feet}'#{inches}" tall]
+I am 6'4" tall
+```
+
+No need to escape the double quote here.
+
+There is a single-quoted version as well using `q`:
+
+```ruby
+> puts %q[I am #{feet}'#{inches}\" tall]
+I am #{feet}'#{inches}\" tall
+```
+
+This is notably less useful than `%Q`. For that reason, `%Q` makes sense as a
+default and it makes up the percent notations unmodified behavior:
+
+```ruby
+> puts %[I am #{feet}'#{inches}" tall]
+I am 6'4" tall
+```