[analyzer] Standardize diagnostic messages that contained multiple sentences across the CSA checkers (#237410)
Until now, there was no consensus between using single spaces or double
spaces after sentence endings in the emitted diagnostics by the Clang
Static Analyzer (CSA). This led to inconsistently formatted diagnostics
by the CSA.
Currently there are the following cases where the CSA is not consistent
with the Clang compiler:
- 1: Using double spaces after sentence endings
- 2: Using multiple full sentences in diagnostics
- 3: Using a capital letter at the start of the diagnostic
#228777 resolves point 1 and partially 2. #236804 resolves points 1 and
2 in `BugReporter`. This PR resolves point 2 in the rest of the Clang
Static Analyzer's checker.
To uplift downstream tests someone needs to convert multiple full
sentences in the test suite to single sentences using `;` or `,`.