Fix `IndexDefect` errors in httpclient on invalid/weird headers (#22886)

Continuation of https://github.com/nim-lang/Nim/pull/19262

Fixes https://github.com/nim-lang/Nim/issues/19261

The parsing code is still too lenient (e.g. it will happily parse header
names with spaces in them, which is outright invalid by the spec), but I
didn't want to touch it beyond the simple changes to make sure that
`std/httpclient` won't throw `IndexDefect`s like it does now on those
cases:
- Multiline header values
- No colon after the header name
- No value after the header name + colon

One question remains - should I keep `toCaseInsensitive` exported in
`httpcore` or just copy-paste the implementation?

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

0 files changed, 0 insertions, 0 deletions