refactor: drop the dead initialiser in gen_utf_char

[blaipr]

b = 'b' in gen_utf_char is never read. is_char starts False, so the loop below always runs at least once and rebinds b to the integer chr() is given, on every path that reaches the return.

 def gen_utf_char():
     is_char = False
-    b = 'b'
     while not is_char:
         b = random.randint(32, 0x10FFFF)
         is_char = chr(b).isprintable()
     return chr(b)

It was not harmless. It is the only reason the type checker believed chr() could be handed a string, reporting Expected SupportsIndex, found Literal["b"] | int for a call that cannot receive one. ty goes from 35 diagnostics to 34.

Verification

• 2000 draws of gen_utf_char() all return a single printable character within the range the randint call specifies, so the loop's contract is unchanged.
• random_utf8 and random_title(non_ascii=True), the two callers that reach it, still produce what they did.
• ruff format --check, ruff check and the unit suite (366 passing) are unchanged.

The is_char sentinel is left alone. It is an ordinary loop variable rather than dead code, and rewriting the loop is a larger change than this one is.

[ciq-it-service-account]

✅ Snyk checks have passed. No issues have been found so far.

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