Autocompleting IJ1 macros built-in functions adds a new line character after completion

[ndefrancesco]

When autocompleting some IJ1 built-in functions (and related), the completed text comes with a trailing new line character, effectively making the cursor to jump to the next line after insertion.

This behaviour only appears with (a fair amount of) entries that are parsed from functions.html and functions_extd.html.

This issue was reported by Nuno Pimpão Martins (thanks!), and is discussed in this forum topic: Auto-completion introduces new line/carriage return on item select.