remote.h: fix space indentation in get_remote_group declaration

[Copilot]

The check-whitespace CI job was failing due to space-indented continuation lines in the get_remote_group function declaration added in commit 3e7b9dce27.

Changes

• remote.h: Replace leading spaces with tab+space alignment on the get_remote_group parameter continuation lines, consistent with git's coding style

 int get_remote_group(const char *key, const char *value,
-                    const struct config_context *ctx,
-                    void *priv);
+		     const struct config_context *ctx,
+		     void *priv);

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