Crash opening big files

[llucasll]

 * Xed 3.2.2
 * Distribution - Linux Mint 20.3 Cinnamon

Issue

Xed crashes when opening large files (also losing all other opened and sometimes changed files).
Sometimes you simply opened the big file accidentally, (e.g. by the GUI, using nemo (File Manager)) and have no way to cancel the operation.

It could gracefully fail to load them, instead.

Steps to reproduce

Simply try to open a file with ~10MB or more

Expected behaviour

• Xed could emit a warning before trying to open big files, advising the user and asking for confirmation;
• or only load a reasonable part of the file in memory at a time, avoiding the crash;
• or even, at least resource, refuse entirely to open the file because of its size (clearly the simplest solution to implement).

[kacperpaczos]

I can reproduce it. I use this file.
norm_wiki_sample.txt