internal/labels: copy descriptions from repo

For the labels that exist in the golang/go repo, copy their descriptions
into our config. Also, reword existing label descriptions to follow the
common pattern used in the repo.

The labeleval tool shows that these changes make minimal differences:

--- /tmp/before-desc-changes.txt	2024-12-13 16:32:46.735167620 -0500
+++ /tmp/after-desc-changes.txt	2024-12-13 16:37:44.330625628 -0500
@@ -3,7 +3,7 @@
 69003  PASS:5 FAIL:0   accessRequest:5
 69005  PASS:5 FAIL:0   libraryProposal:5
 69008  PASS:5 FAIL:0   languageProposal:5
-69011  PASS:1 FAIL:4   question:1  bug:1  languageProposal:3
+69011  PASS:0 FAIL:5   bug:3  languageProposal:2
 69012  PASS:5 FAIL:0   bug:5
 69014  PASS:5 FAIL:0   bug:5
 69015  PASS:5 FAIL:0   bug:5

For #64.

Change-Id: Iaf7e0b3542cc2f852eb28ca8e178a0af307cebfa
Reviewed-on: https://go-review.googlesource.com/c/oscar/+/636476
Reviewed-by: Ian Lance Taylor <iant@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>

internal/labels/static/categories.json

@@ -3,62 +3,62 @@
     {
       "Name": "bug",
       "Label": "BUGLABEL",
-      "Description": "This issue describes a bug in the Go implementation."
+      "Description": "Issues describing a bug in the Go implementation."
     },
     {
       "Name": "languageProposal",
       "Label": "LANGPROPLABEL",
-      "Description": "This issue describes a requested change to the Go language specification."
+      "Description": "Issues describing a requested change to the Go language specification."
     },
     {
       "Name": "libraryProposal",
       "Label": "LIBPROPLABEL",
-      "Description": "This issue describes a requested change to the Go standard library or x/ libraries, but not to a tool"
+      "Description": "Issues describing a requested change to the Go standard library or x/ libraries, but not to a tool"
     },
     {
       "Name": "toolProposal",
       "Label": "TOOLPROPLABEL",
-      "Description": "This issue describes a requested change to a Go tool or command-line program."
+      "Description": "Issues describing a requested change to a Go tool or command-line program."
     },
     {
       "Name": "implementation",
       "Label": "IMPLABEL",
-      "Description": "This issue describes a semantics-preserving change to the Go implementation."
+      "Description": "Issues describing a semantics-preserving change to the Go implementation."
     },
     {
       "Name": "accessRequest",
       "Label": "access requestLABEL",
-      "Description": "This issue is a request for builder or gomote access."
+      "Description": "Issues requesting builder or gomote access."
     },
     {
       "Name": "pkgsiteRemovalRequest",
-      "Label": "pkgsite removal requestLABEL",
-      "Description": "This issue is a pkgsite removal request."
+      "Label": "pkgsite/package-removal",
+      "Description": "Issues for package removal. See https://pkg.go.dev/about#removing-a-package"
     },
     {
       "Name": "automation",
       "Label": "automationLABEL",
-      "Description": "This issue is created by gopherbot or watchflakes automation."
+      "Description": "Issues created by gopherbot or watchflakes automation."
     },
     {
       "Name": "backport",
       "Label": "backportLABEL",
-      "Description": "This issue is created for requesting a backport of a change to a previous Go version."
+      "Description": "Issues created for requesting a backport of a change to a previous Go version."
     },
     {
       "Name": "builders",
-      "Label": "buildersLABEL",
-      "Description": "This issue is about the running of the Go builders."
+      "Label": "Builders",
+      "Description": "x/build issues (builders, bots, dashboards)"
     },
     {
       "Name": "question",
       "Label": "questionLABEL",
-      "Description": "This issue is a question about using Go."
+      "Description": "Issues that are questions about using Go."
     },
     {
       "Name": "workingAsIntended",
-      "Label": "WAILABEL",
-      "Description": "This issue describes something that is working as it is supposed to."
+      "Label": "WorkingAsIntended",
+      "Description": "Issues describing something that is working as it is supposed to."
     },
     {
       "Name": "featureRequest",
@@ -67,13 +67,13 @@
     },
     {
       "Name": "documentation",
-      "Label": "DocLabel",
-      "Description": "This issue describes a change to documentation."
+      "Label": "Documentation",
+      "Description": "Issues describing a change to documentation."
     },
     {
       "Name": "invalid",
       "Label": "invalidLABEL",
-      "Description": "This issue is empty, incomplete, or spam."
+      "Description": "Issues that are empty, incomplete, or spam."
     },
     {
       "Name": "other",