strings: Add nindent function

[binoculars]

Convenience function for working with YAML files, among other things.

Problem

{{ $foo := "bar\nbaz" }}
key: |-
  {{- indent 2 $foo }}

will produce:

key: |-  bar
  baz

We could unindent, and not use white space trimming ({{ vs {{-), but this breaks visual consistency. Another solution may be to pipe to an additional print, but this is inconvenient.

Solution

{{ $foo := "bar\nbaz" }}
key: |-
  {{- nindent 2 $foo }}

will produce:

key: |-
  bar
  baz