Fix serialization related property name problems

[filzrev]

This PR contains following changes.

1.OriginalHomepage changes(88104f6)

JSON/YAML Alias names use wrong spelling names. (OriginallHomepage)
There is compatibility problems. If these name are changed.

But this property is added recently (about 4 month ago) and option is undocumented. (#7736 (comment))

So there is almost no impact by changing these name settings.

2. EnableSourceInfo changes(88104f6)

Change JSON property name to enableSourceInfo.
It seems there is no compatibility problems by this changes.

[codecov]

Codecov Report

Patch coverage has no change and project coverage change: -0.01 ⚠️

Comparison is base (c1545fe) 76.90% compared to head (88104f6) 76.90%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8941      +/-   ##
==========================================
- Coverage   76.90%   76.90%   -0.01%     
==========================================
  Files         605      605              
  Lines       25088    25088              
==========================================
- Hits        19295    19294       -1     
- Misses       5793     5794       +1     

Impacted Files	Coverage Δ
...DocAsCode.DataContracts.Common/TocItemViewModel.cs	71.73% <ø> (ø)
...oft.DocAsCode.Plugins/MarkdownServiceParameters.cs	100.00% <ø> (ø)

... and 1 file with indirect coverage changes

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[yufeih]

Looks good

[KalleOlaviNiemitalo]

But this property is added recently (about 4 month ago)

The TocItemViewModel.OriginalHomepage property and the misspelling originallHomepage are far older; the attributes [YamlMember(Alias = "originallHomepage")] [JsonProperty("originallHomepage")] were added in #2082, September 2017. But I think this property is intended for DocFX internal serialization only; not for use in YAML metadata, in custom templates, or in external equivalents of docfx metadata for other programming languages.