Make check_symbols not accept dynamic c++ symbols

[Ngalstyan4]

Turns out our static usearch library still depended on the cpp runtime library libstdc++ dynamically.
This usually did not cause issues since postgres
commonly links libstdc++ dynamically so c++ symbols in our .so would be resolved dynamically, when loaded.

This did cause issues for when postgres was not linked with libstdc++. I do not know when exactly this happens but it seems this at least happens when building postgres from source under certain circumstances

This commit makes sure that we do not use libstdc++ symbols from postgres dynamic library dependency and actually enforce that all c++ symbols we require are in the sahred object we build

[codecov]

Codecov Report

Merging #181 (bdcb8bc) into main (39b5b00) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #181   +/-   ##
=======================================
  Coverage   83.29%   83.29%           
=======================================
  Files          17       17           
  Lines        1161     1161           
  Branches      245      245           
=======================================
  Hits          967      967           
  Misses         85       85           
  Partials      109      109           

[github-actions]

Benchmarks

metric	old	new	pct change
recall (after create)	0.740	0.740	-
recall (after insert)	0.738	0.726	-1.63%
select bulk tps	214.972	217.193	+1.03%
select bulk latency (ms)	36.515	36.122	-1.08%
select bulk latency (stddev ms)	8.139	8.295	+1.92%
create latency (ms)	1497.447	1489.314	-0.54%
insert bulk tps	14.138	13.927	-1.49%
insert bulk latency (ms)	70.718	71.789	+1.51%
insert bulk latency (stddev ms)	3.203	2.440	-23.82%
disk usage (bytes)	6348800.000	6348800.000	-