Fix line number widths (#31341)

Fixes regression
#31307 (comment)

Table CSS is weird. A `auto` value does not work and causes the
regression while any pixel value causes another regression in diff where
the code lines do not stretch. Partially revert that PR and clean up
some related too-deep CSS selectors.

<img width="109" alt="Screenshot 2024-06-12 at 15 07 22"
src="https://github.com/go-gitea/gitea/assets/115237/756c5dea-44b8-49f9-8a08-acef68075f62">
<img width="119" alt="Screenshot 2024-06-12 at 15 07 43"
src="https://github.com/go-gitea/gitea/assets/115237/28ae1adc-118e-4016-8d09-033b9f1c9a6f">
<img width="151" alt="Screenshot 2024-06-12 at 15 07 07"
src="https://github.com/go-gitea/gitea/assets/115237/08db7ed9-de4e-405e-874d-c7ebe3082557">
<img width="141" alt="Screenshot 2024-06-12 at 15 07 14"
src="https://github.com/go-gitea/gitea/assets/115237/c4a5492b-1bf1-4773-bc8d-64eb36d823f9">

Author: silverwind

web_src/css/base.css

@@ -1001,6 +1001,13 @@ overflow-menu .ui.label {
   padding: 0 8px;
   text-align: right !important;
   color: var(--color-text-light-2);
+  width: 1%; /* this apparently needs to be a percentage so that code column stretches in diffs */
+  min-width: 72px;
+  white-space: nowrap;
+}
+
+.code-diff .lines-num {
+  min-width: 50px;
 }
 
 .lines-num span.bottom-line::after {
@@ -1020,6 +1027,7 @@ overflow-menu .ui.label {
 
 .lines-type-marker {
   vertical-align: top;
+  white-space: nowrap;
 }
 
 .lines-num,
@@ -1052,6 +1060,7 @@ overflow-menu .ui.label {
 
 .lines-escape {
   width: 0;
+  white-space: nowrap;
 }
 
 .lines-code {

web_src/css/repo.css

@@ -1555,8 +1555,6 @@ td .commit-summary {
 
 .repository .diff-file-box .file-body.file-code .lines-num {
   text-align: right;
-  width: 1%;
-  min-width: 50px;
 }
 
 .repository .diff-file-box .file-body.file-code .lines-num span.fold {
@@ -1582,12 +1580,6 @@ td .commit-summary {
   table-layout: fixed;
 }
 
-.repository .diff-file-box .code-diff tbody tr td.lines-num,
-.repository .diff-file-box .code-diff tbody tr td.lines-escape,
-.repository .diff-file-box .code-diff tbody tr td.lines-type-marker {
-  white-space: nowrap;
-}
-
 .repository .diff-file-box .code-diff tbody tr td.center {
   text-align: center;
 }