Update build docs and AspNetCore.sln (#51900)

* Update build docs and AspNetCore.sln

* Fix count in numbered list

AspNetCore.sln

@@ -7848,22 +7848,6 @@ Global
 		{48E64014-B249-4644-8AEB-CDEE8ABA0DC2}.Release|x64.Build.0 = Release|Any CPU
 		{48E64014-B249-4644-8AEB-CDEE8ABA0DC2}.Release|x86.ActiveCfg = Release|Any CPU
 		{48E64014-B249-4644-8AEB-CDEE8ABA0DC2}.Release|x86.Build.0 = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|Any CPU.Build.0 = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|arm64.ActiveCfg = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|arm64.Build.0 = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|x64.ActiveCfg = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|x64.Build.0 = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|x86.ActiveCfg = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Debug|x86.Build.0 = Debug|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|Any CPU.ActiveCfg = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|Any CPU.Build.0 = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|arm64.ActiveCfg = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|arm64.Build.0 = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|x64.ActiveCfg = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|x64.Build.0 = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|x86.ActiveCfg = Release|Any CPU
-		{1542DC58-1836-4191-A9C5-51D1716D2543}.Release|x86.Build.0 = Release|Any CPU
 		{46FB7E93-1294-4068-B80A-D4864F78277A}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
 		{46FB7E93-1294-4068-B80A-D4864F78277A}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{46FB7E93-1294-4068-B80A-D4864F78277A}.Debug|arm64.ActiveCfg = Debug|Any CPU
@@ -11357,7 +11341,6 @@ Global
 		{987E1C29-F124-40C8-8E6F-1B2B6A4CB62A} = {A5946454-4788-4871-8F23-A9471D55F115}
 		{3CBC4802-E9B8-48B7-BC8C-B0AFB9EEC643} = {0ACCEDA7-339C-4B4D-8DD4-1AC271F31C04}
 		{48E64014-B249-4644-8AEB-CDEE8ABA0DC2} = {3CBC4802-E9B8-48B7-BC8C-B0AFB9EEC643}
-		{1542DC58-1836-4191-A9C5-51D1716D2543} = {05A169C7-4F20-4516-B10A-B13C5649D346}
 		{6126DCE4-9692-4EE2-B240-C65743572995} = {0508E463-0269-40C9-B5C2-3B600FB2A28B}
 		{46FB7E93-1294-4068-B80A-D4864F78277A} = {6126DCE4-9692-4EE2-B240-C65743572995}
 		{25FA84DB-EEA7-4068-8E2D-F3D48B281C16} = {6126DCE4-9692-4EE2-B240-C65743572995}

docs/BuildFromSource.md

@@ -140,7 +140,7 @@ The steps you follow next depend on your preferred development environment:
     ./build.cmd -test
     ```
 
-1. Alternatively, you can use the `dotnet test` and `dotnet build` commands directly once you've activated the locally installed .NET SDK.
+1. Alternatively, you can use the `dotnet test` and `dotnet build` commands, **alongside specific project files**, once you've activated the locally installed .NET SDK.
 
     ```bash
     # Linux or Mac
@@ -170,7 +170,7 @@ If you have [Codespaces enabled on your GitHub user account](https://github.com/
 
     The Codespace will spend a few minutes building and initializing. Once it's done, you'll be able to navigate the Codespace in a web-based VS Code environment.
 
-1. You can use the `dotnet build` and `dotnet test` commands to build and test the repo.
+1. You can use the `dotnet build` and `dotnet test` commands to build and test specific projects within the repo.
 
     You don't need to activate the locally installed .NET SDK or run the `restore` script because it's done during the Codespace initialization process.