Overview

DebugPrinter::print() in src/mongo/db/exec/sbe/util/debug_print.cpp emits misaligned indentation, trailing spaces, and blank lines in SBE plan and expression output.

Problem

• A leading backtick token removes any trailing space from the output, including the indentation written by cmdDecIndent. Closing parentheses and brackets are indented by 3 or 7 spaces instead of a multiple of 4.
• Every line ends in a space.
• Adjacent cmdDecIndent and cmdNewLine commands produce blank lines that still carry indentation.
• The output of slotBasedPlan.stages and cachedPlan.stages ends with a space.

Scope of Work

• src/mongo/db/exec/sbe/util/debug_print.cpp - remove only spaces that belong to the current line, trim trailing whitespace at each newline and at the end of the output, and never emit a blank line.
• src/mongo/db/exec/sbe/util/debug_print_test.cpp - new unit test.
• Regenerate golden outputs under src/mongo/db/test_output/ and jstests/query_golden/expected_output/.
• Update inline expectations in abt_lower_test.cpp and sbe_stage_blueprint_test.cpp.

Acceptance Criteria

• No line of DebugPrinter output ends in whitespace, and no line is blank.
• Every indented line is indented by a multiple of 4 spaces.