Replace refs to "searchErr" & "seekErr" w/ direct links

[grumpyinca]

The message for " ... no free independent variables" does not communicate well. Many users read the pop-up message and go on to read the details in Help but still struggle to resolve the issue.

• Different (expanded?) wording for the pop-up message should be developed.
• Rather than linking to the intermediate searchErr, a direct link to each case the Help detail should be implemented.

Search for all occurrences of "searchErr". Where appropriate, replace "errors.html#searchErr" with: alerts.html#NoFreeIV or alerts.html#Constraint_Inconsistency

Repeat the process with seekErr.

[grumpyinca]

Changes were also made in the doc files:

• alerts.md
• terminology.md

[grumpyinca]

Note that since #857 was built on the current state of this branch, if there are no further changes here and if 857 is merged to master, there is no need to merge this branch.

[grumpyinca]

Merged to master; pushed to remote (origin); closing.

[grumpyinca]

Remove comma in "Seek cannot continue, because ..." (4 places in 3 files).

[grumpyinca]

Re-merged to master; pushed to remote / origin. Closing.