docs: fix typos in code comments and doc strings

[Avicennasis]

Summary

Fixes 23 typos in Go doc comments and one copyright header. Comments only - no code, no identifiers, no behaviour change.

rocksdb/backup.go

• GetCount gets the number backsup available -> the number of backups available
• // GetSize get the size ... -> gets
• // Close close the backup engine ... -> closes

rocksdb/write_batch.go

• // NewWriteBatch create a WriteBatch object. -> creates
• // NewNativeWriteBatch create a WriteBatch object. -> creates
• // Destroy destroys de LogDataExtractor. -> the LogDataExtractor

log/logger.go

• hightest possible rank -> highest
• (e.g. losts of contact with peers...) -> loss of contact
• messages that hightlight the main progress -> highlight
• Trace designates a even finer-grained informational events -> designates even finer-grained informational events (matches the wording of the Debug entry just above)
• Any log trace less sever is supressed. -> less severe is suppressed
• If set, this override InferLevels. -> overrides

client/config.go

• some amount of dely between event replication -> delay
• the time the healtch checker waits for -> health checker
• helthchecks of all endpoints -> healthchecks (both the doc comment and the desc: flag description, so the CLI help text matches)

balloon/hyper/tree.go

• a sparse merkel tree -> Merkle (the spelling used in docs/source/internals/glossary.rst and in docs/source/spelling_wordlist.txt)
• verify a membersip proof -> membership

balloon/hyper/batch_cache.go

• This comes from the intuituion that -> intuition
• In the ASCII tree diagram: 4 -3 -> 4 - 3 (aligns the = with the other three rows), 2 bits => indexes 0..4 -> 0..3, and 3 bits => indexes 0..7 (was 0..8) - 2 bits address 4 indexes and 3 bits address 8, so the ranges were off by one

crypto/hashing/hash.go

• different hashers and their funcionality -> functionality

cmd/agent_auditor.go

• copyright header Banco Bilbao Vizcaya Argentaria, n.A. -> S.A. (223 other files in the repo say S.A.)

Note: the same n.A. header typo also appears in crypto/keys.go, cmd/agent_monitor.go and cmd/agent_publisher.go, and merkel also appears in balloon/history/tree.go. Those were outside the scope of this pass - happy to include them if you would prefer one sweep.

No functional changes - comments and documentation only.