fix over-indenting in diff mode

[tstromberg]

A last-minute change to the terminal UI PR resulted in over-indenting diff's by one space:

Previous:

├─ 🟡 Changed: 3CX/libffmpeg.dylib [CRITICAL → MEDIUM]
│     X anti-static [CRITICAL → NONE]
--       🛑 xor/user_agent — XOR'ed user agent, often found in backdoors, by Florian Roth
│     ≡ cryptography [LOW]
│       🟢 aes — Supports AES (Advanced Encryption Standard)
│     ≡ data [MEDIUM]
│       🟡 base64/decode — decode base64 strings: base64_decode
--       🟢 compression/gzip — works with gzip files
│       🟢 encoding/base64 — Supports base64 encoded strings
--       🟢 random/insecure — generate random numbers insecurely

New:

├─ 🟡 Changed: 3CX/libffmpeg.dylib [CRITICAL → MEDIUM]
│     X anti-static [CRITICAL → NONE]
--      🛑 xor/user_agent — XOR'ed user agent, often found in backdoors, by Florian Roth
│     ≡ cryptography [LOW]
│       🟢 aes — Supports AES (Advanced Encryption Standard)
│     ≡ data [MEDIUM]
│       🟡 base64/decode — decode base64 strings: base64_decode
--      🟢 compression/gzip — works with gzip files
│       🟢 encoding/base64 — Supports base64 encoded strings
--      🟢 random/insecure — generate random numbers insecurely