Handle field names with any characters with a known set of special

[fmassot]

…characters and an escape one for the query parser.

Special characters : + ^ ` : { } " [ ] ( ) ~ ! \ * \s.
Almost like Lucene but without && || -.
The escape character is \.
I kept the restriction on the - which cannot be a first character of a field name.
- can be considered as a special character as it is used by the language query, I did not put it in the special characters for retro compatibility.

• update the query parser to parse such field names
• update is_valid_field_name function to check only if field name has at least one character and does not start with -

[codecov]

Codecov Report

Merging #1109 (a2d60db) into main (92f20bc) will increase coverage by 0.02%.
The diff coverage is 100.00%.

❗ Current head a2d60db differs from pull request most recent head 04c37e5. Consider uploading reports for the commit 04c37e5 to get more accurate results

@@            Coverage Diff             @@
##             main    #1109      +/-   ##
==========================================
+ Coverage   89.57%   89.59%   +0.02%     
==========================================
  Files         202      202              
  Lines       20198    20210      +12     
==========================================
+ Hits        18092    18108      +16     
+ Misses       2106     2102       -4     

Impacted Files	Coverage Δ
query-grammar/src/query_grammar.rs	99.66% <100.00%> (+0.02%)	⬆️
query-grammar/src/user_input_ast.rs	87.67% <100.00%> (ø)
src/schema/mod.rs	100.00% <100.00%> (ø)
src/indexer/merger.rs	89.45% <0.00%> (-0.10%)	⬇️
src/directory/directory.rs	90.24% <0.00%> (+12.19%)	⬆️

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[PSeitz]

Ah nice the coverage report I added yesterday. Seems to be helpful, but not completely accurate.

[fmassot]

Ah nice the coverage report I added yesterday. Seems to be helpful, but not completely accurate.

very nice indeed, would be nice to add it to quickwit.

[fulmicoton]

including special characters, but these needs to be escaped with escape character \.

[fulmicoton]

(I edited a comment and simplified the code a tiny bit)