Docs: add aliases and tweak heading title

[chalin]

• Contributes to Redirect /lang to /docs/lang rather than just /docs opentelemetry.io#665
• Adjusts the title of the first heading to match other SIG landing pages

/cc @austinlparker

[codecov]

Codecov Report

Merging #3765 (c4d716e) into main (69d26c1) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main    #3765      +/-   ##
============================================
- Coverage     89.18%   89.16%   -0.03%     
- Complexity     3870     3920      +50     
============================================
  Files           463      470       +7     
  Lines         12125    12344     +219     
  Branches       1188     1208      +20     
============================================
+ Hits          10814    11006     +192     
- Misses          916      939      +23     
- Partials        395      399       +4     

Impacted Files	Coverage Δ
...metry/exporter/prometheus/PrometheusCollector.java	56.25% <0.00%> (-37.50%)	⬇️
...metry/sdk/metrics/export/PeriodicMetricReader.java	81.66% <0.00%> (-0.88%)	⬇️
.../opentelemetry/sdk/logs/data/LogRecordBuilder.java	93.54% <0.00%> (-0.40%)	⬇️
.../io/opentelemetry/sdk/logs/LogSinkSdkProvider.java	100.00% <0.00%> (ø)
...ntelemetry/sdk/logs/LogSinkSdkProviderBuilder.java	100.00% <0.00%> (ø)
...dk/metrics/export/PeriodicMetricReaderFactory.java	100.00% <0.00%> (ø)
...etry/exporter/otlp/internal/logs/LogMarshaler.java	66.66% <0.00%> (ø)
...porter/prometheus/PrometheusHttpServerFactory.java	77.77% <0.00%> (ø)
...orter/logging/otlp/OtlpJsonLoggingLogExporter.java	84.61% <0.00%> (ø)
...lemetry/exporter/logging/SystemOutLogExporter.java	94.11% <0.00%> (ø)
... and 12 more

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[jkwatson]

👍🏽