docs: replace emojis for better dark mode visibility

[Anca2022]

Description of changes

On https://rafiki.dev/resources/get-involved/ the coding emoji 💻 was hard to see in dark mode, so I replaced it with 👨‍💻

Required

• Used LinkOut component on external links
• Reviewed Vale errors and made changes where appropriate
• Ran Prettier
• Previewed updates in Netlify
• Received SME and/or peer approval if updates are significant
• Included a "fixes #" comment

Conditional

• Ensured sequence diagrams follow our style guide
• Included code samples where appropriate
• Updated related READMEs

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[github-actions]

🚀 Performance Test Results

Test Configuration:

• VUs: 4
• Duration: 1m0s

Test Metrics:

• Requests/s: 42.14
• Iterations/s: 14.05
• Failed Requests: 0.00% (0 of 2540)

📜 Logs

> [email protected] run-tests:testenv /home/runner/work/rafiki/rafiki/test/performance
> ./scripts/run-tests.sh -e test "-k" "-q" "--vus" "4" "--duration" "1m"

Cloud Nine GraphQL API is up: http://localhost:3101/graphql
Cloud Nine Wallet Address is up: http://localhost:3100/
Happy Life Bank Address is up: http://localhost:4100/
cloud-nine-wallet-test-backend already set
cloud-nine-wallet-test-auth already set
happy-life-bank-test-backend already set
happy-life-bank-test-auth already set
     data_received..................: 917 kB 15 kB/s
     data_sent......................: 2.0 MB 32 kB/s
     http_req_blocked...............: avg=8.21µs   min=2.34µs   med=5.48µs   max=3.87ms   p(90)=6.66µs   p(95)=7.12µs  
     http_req_connecting............: avg=664ns    min=0s       med=0s       max=567.48µs p(90)=0s       p(95)=0s      
     http_req_duration..............: avg=94.25ms  min=7.6ms    med=77.4ms   max=496.66ms p(90)=158.53ms p(95)=182.07ms
       { expected_response:true }...: avg=94.25ms  min=7.6ms    med=77.4ms   max=496.66ms p(90)=158.53ms p(95)=182.07ms
     http_req_failed................: 0.00%  ✓ 0         ✗ 2540
     http_req_receiving.............: avg=87.17µs  min=27.09µs  med=76.3µs   max=2.63ms   p(90)=111.36µs p(95)=138.36µs
     http_req_sending...............: avg=36.42µs  min=9.82µs   med=28.15µs  max=2.73ms   p(90)=42.57µs  p(95)=56.81µs 
     http_req_tls_handshaking.......: avg=0s       min=0s       med=0s       max=0s       p(90)=0s       p(95)=0s      
     http_req_waiting...............: avg=94.12ms  min=7.44ms   med=77.28ms  max=496.6ms  p(90)=158.43ms p(95)=181.99ms
     http_reqs......................: 2540   42.140689/s
     iteration_duration.............: avg=284.24ms min=189.11ms med=268.49ms max=1.05s    p(90)=343.35ms p(95)=371.85ms
     iterations.....................: 847    14.052427/s
     vus............................: 4      min=4       max=4 
     vus_max........................: 4      min=4       max=4