Hover and autocomplete can't find macros prefixed with @

[PgBiel]

Describe the bug
When hovering over a @macroname, either nothing is displayed, or any matches for macroname (without @) are shown instead, even if they have nothing to do with the invoked macro (e.g. some function with that same name). Similarly, autocomplete cannot find macro names beginning with @.

This problem can be traced back to the snippet below in SourceCode.getWordIndexLimits in server/pkg/document/sourcecode/sourcecode.go (and possibly similar for Document.getWordIndexLimits in document_reader.go). When the user clicks on an identifier, we only go back as far as there are letters or numbers, but @s are not included in the identifier.

c3-lsp/server/pkg/document/sourcecode/sourcecode.go

Lines 176 to 184 in 116f5fb

	symbolStart := 0
	for i := index; i >= 0; i-- {
	r := rune(s.Text[i])
	if !utils.IsAZ09_(r) {
	// First invalid character found, that means previous iteration contained first character of symbol
	symbolStart = i + 1
	break
	}
	}

One potential solution would be to allow @ as part of symbol names, but I guess this could potentially lead to some problems with @attributes, if those ever get their own form of autocomplete.

Alternatively, we could add a property to Word - or a function - which indicates whether or not there is an @ right before the word, and if so we can include that in the search.

To Reproduce
Steps to reproduce the behavior:

1. Define a macro with @body, which requires an @ prefix, e.g. macro @name(; @body) { @body(); }
2. Hover on '@name'
3. Note that nothing appears, or instead you get the hover info of a function called name

Expected behavior
Macro hover info should appear

Screenshots

Desktop (please complete the following information):

• OS: Linux
• Editor: Zed and VSCode (and others)
• Version: at least 0.3.3

Additional context
There is some related discussion at #103

[pherrymason]

Branch search_on_astB totally circumvents bugs related to string manipulation like one as I can traverse the code through the AST instead of trying to be smart by manipulating strings.
Let's keep this issue open to remember testing this in the new version, but I would not try to fix it in main branch.