fix(compute): ensure trailing newline in fetched discovery doc

[colinmoy]

Fixes a failure encountered during the scheduled run of the .github/workflows/update-compute-discovery.yml automation workflow.

[gemini-code-assist]

Code Review

This pull request updates the update_discovery_doc.sh script to ensure that the fetched discovery document ends with a trailing newline. The review feedback suggests improving portability by separating the option and argument in the tail command (using tail -c 1 instead of tail -c1) and simplifying the echo command used to append the newline.

[gemini-code-assist]

For better portability across different POSIX-compliant environments (such as BSD/macOS and various Linux distributions), it is recommended to separate the option and its argument with a space (i.e., tail -c 1 instead of tail -c1). Additionally, echo without arguments can be used instead of echo "" to append a newline.

Suggested change

	if [[ -s "${TEMP_JSON}" && -n "$(tail -c1 "${TEMP_JSON}")" ]]; then
	echo "" >>"${TEMP_JSON}"
	fi
	if [[ -s "${TEMP_JSON}" && -n "$(tail -c 1 "${TEMP_JSON}")" ]]; then
	echo >>"${TEMP_JSON}"
	fi

[colinmoy]

Done

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.24%. Comparing base (fd8e805) to head (697794b).

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #16407   +/-   ##
=======================================
  Coverage   92.24%   92.24%           
=======================================
  Files        2246     2246           
  Lines      212296   212296           
=======================================
+ Hits       195825   195840   +15     
+ Misses      16471    16456   -15     

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