rose edit: environment variable substitution syntax issues

[matthewrmshin]

• [ ] (From #1966.) rose edit displays strings containing environment variables substitution syntax differently to simple strings, using a different colour and also showing the quotes. However, it's possible to delete the closing quote without rose edit flagging an error.
• [ ] (Reported via email.) Changing the entry of a text box which contains an environment variable. If one clears a text box which contains something like '$ROSE_DATA/$RUNID.astart', and then start typing a replacement entry, the cursor jumps to the start of the text-box after typing in the first character. So if one is trying to type /data, what one gets is data/. Clearing this error and then re-typing fixes things, but one still has to spot it. This problem does not occur for a text box which did not hold an environment variable.
• [ ] (Reported via email.) Inserting an environment variable into a text box. All text-box entries which use environment variables somewhere in them appear in the GUI enclosed in single quotes. This implies that this is the manner in which they are supposed to be entered. However, if one does this, then things look fine until the suite fails with an error. Returning to the relevant panel one sees that what one typed in as, e.g., '$DATADIR/file' has in fact been rendered as '''$DATADIR/file'''. If one is aware of this one can see it by going to a different panel and then returning to the modified panel, when the extra two pairs of quote marks have appeared. (It turns out that the correct way to insert an environment variable into a text box is without any quotes. Exiting then returning to the modified panel shows that the single quotes have now magically appeared.)
• [ ] (Reported via email.) Environment variables and multi-text-boxes. Some GUI entries are meant to have multiple text boxes (e.g. the list of UM branches), the number of which can be controlled by little + or - buttons next to them. However, if one tries to use an environment variable in the entry it collapses the stack of text boxes into a single box with all the entries crammed into it in a single enormously long line.

[arjclark]

For the final point see: #2013 as this is the intended behaviour and there was much conversation round this whole thing at the time and the various "special exceptions" being made.