Replace the only two occurrences of \t in C code

[dtolnay]

The use of hard tabs, where everything else in this project uses 4-space indent, causes the code to be displayed in a misleading way when tab size is anything other than 8, including in GitHub's web UI.

libyaml/src/api.c

Lines 123 to 126 in f8f760f

	if ((char *)*end - (char *)*start >= INT_MAX / 2)
	return 0;
	new_start = yaml_realloc(*start, ((char *)*end - (char *)*start)*2);

[dtolnay]

CI failure appears unrelated.

Using default tag: latest
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