[Enhancement] Improve results provided by WorkspaceSymbols

[pidgeon777]

In the actual implementation it seems that when a user start digiting a symbol name to be searched among the workspace symbols, only symbols starting with that pattern are returned.

For example, if workspace symbols are:

• ASym1
• ASym2
• ASym3
• BSym1
• BSym2

then if a user searches for 'Sym', nothing is returned.

But if the user searches for 'ASym', then the first three symbols are returned.

Would it be possible to return matches for any symbol containing the pattern, not only those starting with it?