* Minor alignments (like setter to ctor)
* FuzzySuggester has a unicode aware flag, which is not exposed in the fuzzy completion request parameters
* Made XAnalyzingSuggester flags (PAYLOAD_SEP, END_BYTE, SEP_LABEL) to be written into the postings format, so we can retain backwards compatibility
* The above change also implies, that these flags can be set per instantiated XAnalyzingSuggester
* CompletionPostingsFormatTest now uses a randomProvider for writing data to check for bwc
Restrict the size of the input length to a reasonable size otherwise very
long strings can cause StackOverflowExceptions deep down in lucene land.
Yet, this is simply a saftly limit set to `50` UTF-16 codepoints by default.
This limit is only present at index time and not at query time. If prefix
completions > 50 UTF-16 codepoints are expected / desired this limit should be raised.
Critical string sizes are beyone the 1k UTF-16 Codepoints limit.
Closes#3596