Document how :max_header_list_size limits are enforced

[ericmj]

The docs said a header block larger than :max_header_list_size closes the connection. A decoded response header list over the limit resets the request with a PROTOCOL_ERROR stream error and returns a {:max_header_list_size_exceeded, size, max_size} error, and promised request headers over the limit reset the promised stream with REFUSED_STREAM. The connection stays open in both cases.

Only the header block fragments buffered while waiting for END_HEADERS are a connection error, when they're over an upper bound on the encoded size of a header list within the limit. The fragment that carries END_HEADERS isn't counted, and the complete block is then judged by its decoded size.

The docs also say that the server setting is :infinity until the server sends it, and that the client setting must be an integer, since put_settings/2 and the :client_settings option raise on :infinity.

[github-actions]

Coverage Report for CI Build 338

Coverage decreased (-0.1%) to 90.426%

Details

• Coverage decreased (-0.1%) from the base build.
• Patch coverage: No coverable lines changed in this PR.
• 3 coverage regressions across 2 files.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

3 previously-covered lines in 2 files lost coverage.

File	Lines Losing Coverage	Coverage
lib/mint/http2.ex	2	95.31%
lib/mint/http1.ex	1	87.11%

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Coverage Stats

Relevant Lines:	1974
Covered Lines:	1785
Line Coverage:	90.43%
Coverage Strength:	713.78 hits per line

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💛 - Coveralls