Fix code smells

[abitmore]

Note: this is identical to #2703, recreated to get around a permission issue related to the sonar-scan Github Actions workflow.

rewind is reserved
prefix increment dropped_count, i, next_block_num for efficiency increment from method call fetch_by_number() could cause undefined behavior parenthesis added for explicit operator precedence order of operations clarified
max 1 nested break

[abitmore]

Superseded by #2705.