Specify a character for escaped substitution

[jobol]

When the name of the variable starts with a character that is normally interpreted within
mustache templating (i.e. "#^/{&!>:") it should be possible to use an escape character.
This commit propose to use colon (:) as first character to escape the first character of
variable name in the variable substitution with escaping.
Writing {{:NAME}} is equivalent to writing {{NAME}} even when
NAME begins with a special character.

It is interesting to see that it specify an optional character for variable
substitution with escaping and not only an escaping character.

[jobol]

I propose the character : but I agree that any character is possible.

I had in fact the issue with a name starting with #

[jobol]

There is a good spec for JSON pointers: https://tools.ietf.org/html/rfc6901

So having a special character (like ':' ) for explicit value substitution would allow to write {{:/root/4}} that uses the json pointer

[jobol]

Maybe the character = is better

[jgonggrijp]

Sorry to keep you hanging for so long and then brutally closing the pull request. As I detailed in mustache/spec#174 (reply in thread), the spec should be updated before the manual, and the source file for the manual is also in a different repository.

(In my defense, I was not yet involved here when you opened the pull request.)