followup #17700 put changelog in wrong file (#17729)

* Allow use of colons inside fmt

allowing colons inside fmt by replacing the format specifier delimiter lets arbitrary nim code be run within fmt expressions.

* oops

* Update strformat.nim

* one space.

* Update lib/pure/strformat.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

* Update lib/pure/strformat.nim

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>

* changed parser to ignore ':' within parens

* Update strformat.nim

* Update lib/pure/strformat.nim

Co-authored-by: flywind <xzsflywind@gmail.com>

* formatting,documentation,backslash escapes

Adding support for evaluating expressions by special-casing parentheses causes this regression: `&"""{ "(hello)" }"""` no longer parses.
In addition, code such as &"""{(if open: '(' else: ')')}""" wouldn't work.
To enable that, as well as the use of, e.g. Table constructors inside curlies, I've added backslash escapes.
This also means that if/for/etc statements, unparenthesized, will work, if the colons are escaped, but i've left that under-documented.

It's not exactly elegant having two types of escape, but I believe it's the least bad option.

* not sure about how this works

* changelog

* changelog

* added json strformat test

* pulled my thumb out and wrote a parser

* more escapes and string tests

* ok, now i'm sure it's broken but cant get a failing test

* found it

* ok, that'll do

* did i delete this?

* spcng

* spacing

* messed up where changelogs are supposed to go

* ocd

Co-authored-by: Andreas Rumpf <rumpf_a@web.de>
Co-authored-by: flywind <xzsflywind@gmail.com>

changelog.md

@@ -38,6 +38,7 @@
   unless `-d:nimLegacyHomeDir` is specified (for a transition period).
 
 ## Standard library additions and changes
+- Added support for parenthesized expressions in `strformat`
 
 - Added `sections` iterator in `parsecfg`.
 

changelogs/changelog_X_XX_X.md

@@ -13,8 +13,6 @@ The changes should go to changelog.md!
 
 - Changed `example.foo` to take additional `bar` parameter.
 
-- Added support for evaluating parenthesised expressions in strformat
-
 ## Language changes